The Third Incubation of Peacocks, afternoon.

I write this from a lily pad floating on the North Pole. I came here to ponder mushrooms; I find it helpful to think about dark things in bright places. Kaida has scolded me for wading in the algae pools, and I understand how important they are to our oxygen cycle. But they looked so inviting. The golden light from the solar projectors turns even the most ordinary algae blooms into tapestries woven by witch queens. Or landscapes on ancient maps, picked out in lapis lazuli and verdigris. Or … Oh, it’s so difficult to put into words! At any rate, I promised myself I’d try to write from different perspectives, and lying on a giant water lily is a different perspective to be sure.

The Great and Solemn Task of the day was to retrieve six peacock eggs from cold storage on Taiga Level and take them to Kitchen Level for incubation. I’m tremendously excited for them to hatch; I’ve only seen peacocks in books. Kaida is old enough to remember the Second Incubation of Peacocks. Ten were incubated and seven hatched, but about two hundred days later Uncle the Computer announced there was an oxygen cycle imbalance and their number had to be reduced to four. Kaida remembers the culls made good roasts and, afterwards, soup. The survivors died later of various complaints. Mostly the foxes got them. If foxes weren’t so handsome, I think we’d shoot them out an airlock.

The First Incubation of Peacocks was before either of us was born. According to the records no eggs hatched. That happened a lot back then, before anyone knew how to do Tasks very well. But anyway our atmosphere has been oxygen heavy of late, so Uncle agreed we could try peacocks again.

I came up with a thrilling Ceremony for it. We wore blue cloaks made from bedsheets and decorated our hair with lorikeet feathers. We went barefoot. Kaida carried the eggs in our best green tablecloth while I scattered sweet-smelling herbs: specifically marjoram, which we have too much of at the moment, and coriander, which neither of us likes very much. We placed the eggs in the incubator with satisfying solemnity and chanted a spell I wrote for the occasion. Then we swept up and had watercress omelettes for lunch.

Afterwards Kaida sent me to the North Pole for more cress. “And silkworms,” she added. “Otherwise His Lordship will feed us another supper of petri steaks, and I can’t do it, Cat; I’d rather waste away.”

His Lordship is what we call Uncle the Computer when we’re cross at him for ordering us around. He worries about our protein consumption. If we don’t eat enough, he assigns us leftover cloned meat, which is dreadful. It’s been tens of days since any of the animals died, and we’ve had no good reason to slaughter one. The one chicken left in the deepfreeze is emergency rations.

So here I am on the North Pole, at one end of our long, glass fairy tower. The other end is the South Pole, of course. Kaida has been trying to teach me about the Tower’s magnetic poles and how they help keep the engines running and the gravity wells balanced, but it doesn’t come easily to me. Not the way gardening and gene editing and making up new Ceremonies does.

“Of course we have different strengths,” says Kaida. “That’s why two of us are needed in the Tower.”

The last time she said that she sighed, quietly, but with a flourish, and gazed down the window over the four o’clock solar sail. She looked just like the Lady of Shalott or the Princess of Barsoom. Or am I imagining that I remember a sigh? The gravity is lighter here at the North Pole and the oxygen is thicker, and the combination makes me go romantic.

I’d better roll off my lily pad and get back to work. If I don’t report back soon, Kaida will climb down to Control Level and find me on the monitors. Writing ought to be a private thing.

The Thirty-Ninth Harvest of Strawberries, noon.

Ripe strawberries on Rose Level! The southern water filters need cleaning and Orchid Level is overgrown, but Kaida and I agreed we could set a day aside for agreeable work. We dressed in ceremonial pink, got the fruit baskets out of storage, and climbed down.

“The soil’s getting tapped out,” I said. “Next season we’ll have to plant this field with rye.”

Kaida wrinkled her nose. “We still have rye left over from two seasons ago. It makes dense bread and nasty porridge.”

“And good beer,” I reminded her. Kaida likes beer and wine. Most of our beer at the moment was brewed from quinoa, a technically successful experiment with underwhelming results. We have to drink it so it doesn’t go to waste, but replacing it with something decent will be a pleasure. Kaida considered the prospect.

“Strawberries, though,” she said.

“Come on. We’ll make plenty of preserves.”

The strawberries were fat and shiny, begging to be picked. Even so, I could see we’d have a smaller haul than last season. Maybe I ought to rotate the strawberries out for three or four seasons just to be sure. What could I plant to ease Kaida’s disappointment? Another guava on Orchid Level, maybe. Or a birthday melon splice. Or talk to Uncle about unfreezing cacao or coffee seeds. His Lordship is extremely conservative about stimulants. We’ve only been allowed five Harvests of Tea.

Adrift in cultivating thoughts, I filled my baskets without paying much attention to my surroundings. Kaida loves Rose Level, but the heavy perfume—as if the roses weren’t enough, the lavender clippings we brought down from Kitchen Level on the last Day of Herb Cultivars have spread like a purple plague—gives me a headache. It’s soporific as well. I flopped down under the Queen Elizabeth rose tree and pulled my diary out of my apron pocket.

So here I am, basking and writing and thinking about mushrooms again. I might like to make a new mushroom for my birthday present. The one active species of Pleurotus in the Tower is engineered to grow inside our pipes as part of the water filtration system, but its genotype could easily be tweaked into a good culinary species. But if I use my birthday wish on splicing a new mushroom, I won’t be able to make something special for Kaida. A dilemma.

I wonder what Kaida is planning for her birthday. For her last one she installed more windows, a disappointing use of a birthday wish in my book. She enjoys gazing down at the stars, but nearly all the Levels have windows underfoot now. It wasn’t anything new. Not like the birthday when she introduced the amped-up solar projectors that, she says, simulate sunlight on the historical Earth surface to 90% accuracy. Or the birthday she built a garbage disposal. Kitchen duty has been so much better since the garbage disposal.

I’ve let my pen wander again. Perhaps it’s a sign I should put my diary away and look for Kaida. I have no idea where she’s gotten to. Probably collecting rose hips and reciting poetry. I am Sense and she is Sensibility—we agreed the first time we read Jane Austen—and I could never pull off saying “Euclid alone has looked on Beauty bare” to a Great Maiden’s Blush. But I’ve seen her do it.

Evening.

Jotting down a few final lines in bed while Kaida performs her nightly ritual of setting her hair, balancing the Tower’s energy tables, and rubbing avocado and lemon on her skin. I think it makes her look like her face has an outbreak of lichen, but she does wake up smelling like an elegant breakfast. She’s humming to herself as she scrolls through long lists of longer numbers, which may be a sign that her mood has improved. Or it could be another symptom of the problem. I’d better write what I can about the rest of the strawberry outing.

I found Kaida draped across one of her enormous windows, posed like Ophelia. She looked splendid, but it irked me that she hadn’t managed to pick more strawberries. Or rose hips. Lying under the Queen Elizabeth had gotten me in the mood for rose jam and rose hip tea.

“Oh, Cat,” she groaned. “Dearest Cat. I’m so very lonely.”

“Of course you’re not,” I said. “You have me, and Uncle the Computer, and all the animals, especially Rudolf.” Rudolf is our current favorite fox.

“That’s not enough.” She sat up, immediately regretful. “Oh, I don’t mean you, Cat. You’re lovely. But Uncle’s not a person, and the animals are animals. You’ll understand when you’re older.”

I don’t like it when Kaida treats me like a baby just because she has five years on me, but I decided not to argue. She seemed so despondent. I began to worry she might be in a serious mood, one that wouldn’t be cured by coffee or fruit.

I had some confirmation I was right when, as she returned to the strawberry field, I heard her murmur, “I ought to have someone to love.”

Oh dear.

The 512^th Cleaning of the Southern Water Filters, late.

Life can’t be all strawberry picking and dreaming under the roses. The water was coming out of the faucets slightly beige, and this morning Uncle confirmed that the filtration system was overdue for a cleaning. I remember thinking, as I picked at my rye porridge, how this Great and Solemn Task would take the entire day and we had nothing to look forward to but grime and boredom.

If only I’d known!

But I’m getting ahead of myself. I should put everything down before I forget. We pulled on hip waders, rubber gloves, and our nastiest smocks and slipped behind the dining room wall.

The access spaces in the Tower are unlovely in a timeless way. There must have been corridors like this, exactly like this, from the dawn of civilization: yellowish, stale-smelling, always with a bucket and an old magazine abandoned on the floor. I’m sure prehistoric caves had them. They’re in every Level of the Tower but the North Pole, which was designed to be self-sustaining in case of ancient emergencies of some kind. When I was little I liked to sneak through them, pretending to be a thief or a ninja. After Kaida read me The Count of Monte Cristo, every maintenance closet became a dungeon in which to languish.

Now that I’m older, it’s hard to conjure any sense of adventure out of a day in the South Pole access corridors, pulling filtration panels, scrubbing them in a greywater industrial sink, hauling them back into place, and pulling more. One makes certain sacrifices to grow up.

Kaida yanked on the panels as if they’d personally insulted her. Her wistful mood had curdled into a sulk, as I feared it would. She gets this way from time to time, and the times have been coming more often. It’s probably glands. She’s eighteen, and all the novels I’ve read suggest that’s a difficult age.

Then it happened. One awkward yank and Kaida pulled an especially dripping panel down on her head, leaving her face striped with what we always call “muck” so we don’t have to think about what specifically goes into it. She looked about to cry, so it really was terrible of me to burst out laughing.

“I’m sorry!” I said to her accusing glare. “I can’t help it. You need to see yourself.” Somehow the angrier she looked the funnier it got.

There was an electrical cabinet nearby with a reflective steel door. I steered her in front of it. She stared at her muck-striped face, mouth slack. Then she started laughing too.

“I look like a disappointing genetic experiment,” she said. “Part woman, part tiger, part smell.”

I started to make a comment about becoming a beast that haunts the maintenance closets when a crackling sound filled the corridor. I’d never heard anything like it in my life, and only now, hours later, do I realize it was the outer communications network coming online.

“Hello?” said a voice. A low, rough voice, like a bear would have. I’ve only seen bears in pictures, they’re much too big for the Tower. “Requesting rendezvous. Any systems reading me?”

Kaida and I stared at each other. I said, “Go get cleaned up. I’ll take care of it.” I don’t know why I said that. It seemed right.

Kaida nodded and clambered up a ladder. I ran down the corridors, hoping I remembered the way to the docking port. We’d never had a reason to use it.

By the time I got to Control Level, Uncle had switched everything on. I’d never spent much time there, but once in a while I’d come down with Kaida to perform scheduled maintenance Tasks. Sometimes she watched the security monitors. “It’s pleasant to watch all the Levels at once,” she told me. “When the balance is good you can see how they work together, like an antique watch.”

The monitors showing the views outside the Tower were caked with dust. I rubbed them clean with my sleeve. Out in the darkness hovered a small white thing. It looked like nothing in particular.

“Respond, respond,” said the ancient speakers.

Static, and the speakers took on another voice: “My God, it’s one of the Essex stations. It’s still active. Stuart, it’s still active.”

“Are you sure?”

“Look in those viewports. You can see green.”

The first voice swore imaginatively.

“Watch your language,” I said. “There are ladies present.”

There was a very long silence. Then low whispers, followed by the first voice saying, a little too loudly, “Essex, how many crew on board? Report.”

“There’s two of us,” I said. “We live here. Do you want to come in or not?”

Another silence, then, “Affirmative. I mean, we do.”

I told Uncle to grab the ship with the Tower’s umbilical as soon as it came in range. The little white blot grew into a large grey carbuncle with unsettling speed. I had just enough time to learn that one of our visitors was Donald and the other was Stuart before they were ejected from their craft and deposited in a chamber that, if the docking systems still worked, would shower, gas, and irradiate microbes away.

When, hopefully hygienic, Donald and Stuart stepped into the Tower proper, I was the first sight they clapped eyes on. To be brutally self-critical, they could have had better luck. I was still dressed for cleaning the filtration system, still filthy, and surely not smelling my best. I had pinned my hair up that morning, but it had escaped and drifted around my head like a raincloud waiting to be told whose picnic to ruin. My feet were bare as usual.

Happily for Donald and Stuart, the second thing they saw was Kaida.

She stood in the doorway to Orchid Level, the biome just below Control Level, bathed in sunlight of her own creation. She’d washed most of the muck off herself and changed into white. In her hair she wore her favorite piece of jewelry, a pearl garland passed down from the ancient engineers. Framed by banana leaves and orchids, she looked like a fairy queen.

What did our guests look like? I can hardly say. They only registered as big. Big voices, big shadows, big boots clanging on the walkways and leaving no mark. It seemed ridiculous to think they could do anything with their thick paws. They weren’t like the men in novels. I tried not to be disappointed.

“Welcome to Hopewell Tower,” said Kaida.

They dropped to their knees.

The 300^th Fishing Trip, very late.

I’m sorry for falling behind on this diary. So many things have happened. But only one thing matters. It was this afternoon. Nothing will ever be the same.

Oh, well, I ought to write the rest of it down. Someday another girl may be reading this and need the information. What else was there?

The men dropped to their knees. It wasn’t for Kaida, or not entirely. It was for the plants.

“Algae,” said Stuart. “Just algae. That’s how we get our oxygen, our food, everything.”

“You make colonial life sound barbaric,” said Donald. There was a warning purr beneath his words. He thought Stuart was talking too much; he wanted to impress us instead of admitting weakness. Our bush babies do the same thing when we disrupt their territory. But for all the threat display in his voice, his eyes remained wide, soft, and fixed on the tangle of greenery.

I was glad we hadn’t gotten around to pruning Orchid Level. It looked spectacular.

“Oh, and we have a few fungal cultures,” said Stuart. “Sorry, have you girls been … living here?”

“All our lives,” I said. There was a hint of threat display in my voice, too. “Surely you don’t live on algae and mushrooms. What do you do for eggs? Cheese? Lamb chops?”

I knew they didn’t have any of those things. I knew it! It was over two thousand days in our history before the Tower was balanced to support significant animal life, and if our visitors were living off fungus and algae they could hardly have a biome with livestock. I was showing off by mentioning chops. Wildflower Level supports all of eight sheep, the largest herd the Tower has ever been able to sustain, and in my whole life we’ve had only two Days of Mutton Slaughter. We do have lamb in season, but only because we have to kill nearly all new lambs to keep the population low. Lamb chops are a rare treat, and cheese is rationed, but I wanted to see our guests’ eyes pop.

It worked, at least once they figured out I meant real eggs and milk and meat. “Are you telling me,” said Donald, “there are animals here? Nonhuman animals?”

Kaida smiled and beckoned them into the orchid jungle.

Now, as I lie in bed writing this, I know the poor things would’ve been impressed if I’d mentioned a plate of grubs or squirrel stew. They’d probably even slaver at the cloned steaks. Or, no, maybe our cloned meat is they type of thing they’ve eaten before. No matter how Donald tries to hide it, I get the impression their colony on Mars isn’t a very nice place.

It was satisfying to watch them gawk at the banana trees, the lianas, the macaws, the bush babies that jumped on their shoulders and ate from their hands. It was satisfying to mention casually that Orchid Level was only one of five biomes, not counting Quarter Level and the Poles. It was beyond satisfying to take them up to Wildflower Level to milk the sheep. The morning glories were out of control and will be a serious problem if we don’t intervene soon, but our guests didn’t notice that. They loved everything.

Everything except us, it seemed. Again and again, they asked if we were the only human residents of the Tower.

“But surely there used to be people here,” said Stuart for the third or fourth time.

“Of course,” said Kaida, infinitely patient. She really was amazing. You’d think we had guests every day, that these weren’t the first in the Tower’s long history. “But since my mother died, Cat and I have been alone.”

“And you’ve survived all this time? Just the two of you?”

“There were never many of us. It’s hard for the Tower to support large mammals.” The men laughed at that. I don’t know why. It’s true. “For a long time, His Lordship has had the residency set low.”

“His Lordship,” said Donald sharply. “Who’s that?”

It was my turn to laugh. “That’s what we call Uncle.”

“And Uncle,” said Kaida, “is what we call the Tower computer.”

Conversations like this annoyed me. How could these men want any more people around when they had Kaida? I’ve never felt lonely with Kaida around. Kaida sometimes feels lonely with me around, but that’s just glands.

I’m trying to remember all the interesting things that happened. Really, everything was interesting through our guests’ eyes. They gobbled every meal, though they threw up after their big welcome dinner. “I guess our digestive systems aren’t used to real food,” said Stuart. It was a waste of our last frozen chicken. Since then we’ve cooked them simpler recipes—mealworm stir-fry, peanut stew with egg, sweet potato mash, banana crepes—which have gone down with just as much gratitude, and stayed down.

There’s plenty of room for them on Quarter Level. It has ten apartments with two bunks each. Imagine the ancient engineers of the Tower thinking it could produce food and water and oxygen for twenty people! No wonder the early records are full of so much misfortune. Kaida and I share quarters, but over the years we’ve spread into most of the other apartments: one is our spinning, weaving, and sewing room, one is our library, one is full of childhood crafts we keep meaning to pack away. We managed to clear an apartment for Stuart and another for Donald. They were excited by this, too.

The picture I get of their colony is of too many people and not enough of anything else.

Oh, yes. The colony Stuart and Donald come from is probably the last human population alive besides Kaida and me. I suppose that’s worth writing down.

“Earth is barren,” said Stuart over this morning’s breakfast (rye porridge with bananas, strawberries, and gasps of ecstasy from our guests).

“We don’t know that,” said Donald.

“Fine. There may be simple life. Molds. But from low orbit it looks like a muddy rock. It hasn’t recovered from the Great Collapse. You know about the Great Collapse?”

Kaida poured tea. “Yes. It’s when the Tower left because people on Earth didn’t want it anymore.”

“The hell?” said Donald.

“That’s … not wrong,” said Stuart. “Sort of a folk version of the truth. You see, this station was one of a series of arks sent into space around the time the Collapse started. Originally they were test runs for space colonies, and after those plans fell through they became a way to preserve extinct environments. Yours has been unexpectedly successful.” I noticed his gaze dart to Kaida. Whenever he said something clever, he checked to see if she was impressed. Donald did the same thing whenever he pulled a dominance display on Stuart.

I already knew where the Tower came from. As if we needed to be told about our own home! Our guests consider origins enormously important for some reason. They talk about Earth all the time, certainly more than they talk about their colony on Mars, a subject that makes them tight-lipped and grim.

“My point is,” said Stuart, “there’s nobody left on Earth. We spent a week in orbit, taking pictures, searching for signals … No luck.”

“We don’t need to go into the details of our mission,” said Donald.

“They ought to know. This old satellite could be the only human outpost left outside our colony.” Stuart popped a strawberry into his mouth. “There were other Mars colonies, but they haven’t responded to our signals in years.”

“That’s enough,” said Donald.

“I’m trying to get across how important this is. How important you are.” Stuart looked at Kaida and me, but mostly at Kaida. “We thought our mission was a failure, and then we found you.”

Reluctantly, Donald nodded. “We were sent out to search for signs of surviving human life.”

“Why?” I said. “You can’t even feed your own colony.”

Kaida swooped in. “Enough dawdling over breakfast. We’d better get started with the day.”

Donald pushed his chair back. “Something we can help with?”

“Absolutely,” said Kaida. “We’re going fishing.”

Our guests got too excited about this to think about anything else. This was a relief, as I wasn’t in the mood for another dull discussion of why they wanted to find people. It’s such a strange preoccupation. Why look for more people when you don’t know what to do with the ones you already have?

Taro Level was in good balance. Kaida had weeded the terraces recently, and the taro and sweet potatoes were coming along. Soon it would be time for another Harvest of Root Vegetables and another Preparation of Taro Leaves. The fish pond was clear. Tilapia and channel catfish slid between the shadows of the sheltering leaves.

Kaida and I waded in. Stuart and Donald yanked off their boots and followed, soaking their hastily rolled trousers. Wading in water was another new pleasure for them. The trouble came when we caught a fish. Our guests blanched at the creature thrashing in Kaida’s net. They’d never seen an animal—a nonhuman animal—killed.

It was no use explaining that if we didn’t have regular Days of Fishing, the fish would become too large and numerous, eat up the smaller pondlife, and foul the water. Then there would be no fish or snails or crawfish and the brackish water would make the taro sick. They knew that. But there’s a deep, muddy furrow between knowing the fact of something and seeing it before you. Reading books about men was nothing like having breakfast with real ones, and understanding aquaculture was nothing like making a catfish dance in a net, its gill slits flashing red.

Kaida took Donald up the terraces to pull sweet potatoes, but Stuart insisted he could control his panic and learn to catch a fish. I guided his net. His hands weren’t as rough as they looked. He really is almost a person, I thought, and laughed to myself.

“Thanks,” said Stuart. “I want to learn.”

“There’s a skill to it,” I said, “just like any Task.”

He gave me a funny look. “How old are you, Catherine?”

“Cat, please. And thirteen.” My face felt hot. Suddenly I didn’t want to be thirteen, not there in the warm water with my hand on this bulky male animal’s hand. I would have liked to have been older and sophisticated, and perhaps someone else entirely.

“I still can’t believe you and your sister have been running this whole station.”

“All a matter of practice.” I tried to sound as adult as possible. “That’s why we have the Tasks and the Ceremonies. I’m in charge of Ceremonies, you know. Kaida never can think of good ones.”

“Your sister’s very pretty,” said Stuart, as if this observation flowed logically from her inability to think up Ceremonies. “It’s funny. You’re definitely sisters, but you’re so different. I mean,” he added quickly, “you’ll be pretty, too, when you’re grown up. I’m sure.”

That didn’t make me feel any better. In fact, when I thought about it later, it made me feel worse.

But then a catfish swam almost between Stuart’s legs and I swooped his hands down. The net came up full. The catfish twisted and gulped and sprayed water. Stuart barked out a laugh of surprise. And that was when it happened, Stuart. That was when I fell in love with you.

I’m sorry I made you throw up a few minutes later, when I gutted the fish.

We had fish dinner that evening, of course, with a special Ceremony because it was the 300^th Fishing Trip and we always do Ceremonies for round numbers. I made a centerpiece of North Pole water lilies and daffodils. We clasped hands around the table and sang the Ballad of Fiddler’s Green. At least, Kaida and I sang, and our guests sort of hummed along.

You held my left hand. It wasn’t so clumsy after all. It was warm.

Uncounted Day of Soil Chemistry Analysis, Uncounted Day of Rain

Oh, I am in agony! Both our guests are in love with Kaida. This morning they clambered over each other to help her collect soil samples, one of the dullest of all the 517 recorded Tasks. Excitement over soil samples must be love. The three of them mapped out a route that would avoid the rain showers scheduled for all but Taiga Level, leaving me to my own lonely devices.

Soil analysis is one of the Tasks that’s so old and so frequent we don’t have a record of how many times it’s been done. The same goes for rain. Imagine not thinking rain was important enough to write down! On the First Day of Scheduling, when things started to get properly balanced, the people of the Tower made a list of the Great and Solemn Tasks, and Writing Down the Tasks was the very first Task on the list.

So here I am in the mushroom germination room on Kitchen Level, or the Mush Room as Kaida calls it as a not particularly clever joke. None of Kaida’s little jokes are very funny to me now. Stuart, why can’t you understand my feelings? Why must I be thirteen and Kaida eighteen? Why can’t Kaida and Donald fall in love, and you and I fall in love, and everyone pair off neatly? We could have a double wedding like the end of a Shakespeare comedy. Right now it’s Act II of A Midsummer Night’s Dream and we’re mismatched and lopsided and lost in the wood.

I shouldn’t dwell on my miseries. I ought to think about bright things in dark places. I’ll plan my birthday present instead.

I tried to explain birthdays to you last night, Stuart, because mine is coming up soon. Donald was down in the control room, trying to urge the disused equipment back to life. He’s become fixated on contacting his colony. What Donald really wants is to get back to his ship, which Uncle still holds in dock. But we used quite a bit of electricity getting our guests on board, not to mention all the air automatically flushed from the decontamination chamber, and we can’t afford to have people going back and forth through the airlock willy-nilly. Or so Kaida says.

So Donald was in the control room doing whatever he thinks is so important, leaving me gloriously alone with you.

“You mean the birthday girl has to give the present?” you said.

“Of course,” I answered, very sensibly I think. “That way, you can be sure to get what you want.”

You chuckled. I’m not sure if I like your chuckle. It’s enchanting, naturally, but I worry that you think of me as a silly child, and the thought is death. The agony of love! It is exactly like it is in books after all.

“And what do you want for your birthday?” you asked.

“I haven’t decided yet.” You, you, you, but of course it can’t be you; it has to be something I make. “It’s the only time Uncle lets us add something new to the Tower, you see.”

We were strolling through Orchid Level, so I pointed out a company of lorikeets in a guava tree and told you I’d incubated the first eggs on my second birthday. That was before I got old enough to make my own presents, so Kaida let me pretend the eggs were my idea instead of Uncle’s. Later I started making my own, as Kaida did. I engineered two of the butterfly species on Orchid. The first is a wood nymph/painted lady cross that doesn’t improve much on the base genotypes except for looking prettier, but the other is a blue swallowtail modified into a spectacularly efficient broad-spectrum pollinator. It was my tenth birthday present and I’m still proud of it.

I showed you my swallowtails; there are a lot of them now. Soon we may need to increase the bird population to bring them in line. Then I had to ruin everything by mentioning that I’d named the species after Kaida. All at once you turned gooey and started commenting on what a perfect name it was for such beautiful creatures, which was true but somehow not at all what I wanted to hear. Right up to that moment I’d been thinking how perfect the mood was, and how Orchid Level is much more romantic than Rose Level with its strawberries and perfume. But now the romance is spoiled for me.

Maybe I can show you Taiga Level and create a romantic atmosphere there. No, no, there’s nothing romantic about Taiga Level.

The Third Day of Mutton Slaughter, morning.

Well, our guests will be having red meat after all! After measuring the carbon dioxide in the soil, Kaida and Uncle the Computer have worked out that we need to slaughter at least two sheep, as well as a number of smaller animals, to free up oxygen for Stuart and Donald. Also, I have to spend the morning starting as many cultivars as I can in Kitchen Level while Kaida goes into the sewage system and forces the composting process forward.

Kaida and I put a cheerful face on it, promising mutton stew and a first-rate Ceremony after the slaughter, then sent our guests to Rose Level to pick strawberries. But Kaida’s face is tight with worry.

“It’s taken so long to get the Tower balanced for two people,” she whispered to me as we washed the breakfast dishes. “It can’t support four.”

“Not now,” I said.

“Perhaps not ever,” said Kaida.

Ten or twenty days ago, that wouldn’t have bothered me. The Tower was the universe, and two was the only population imaginable. But that’s not the case anymore, is it, Stuart? When you talk about your crowded Martian colony—thirty people, maybe forty, you and Donald keep correcting each other—as if it were too small, I hardly believe it. You and Donald risked your lives looking for more people when you had thirty! It’s so strange.

But I’m beginning to understand. I dried the breakfast plates, thought of living with only Kaida, and for the first time the thought made me sad.

The Third Hatching of Peacocks, afternoon.

To think this was going to be just another Day of Preserves! Not that any day is ordinary with you, Stuart, and to a lesser degree with Donald. It was so much fun to show you how to make strawberry jam. Preserves is a fun Duty. I usually bake bread the day before so Kaida and I can have jam sandwiches while we work. This time I forgot to make bread, so we had to make do with stale rice crackers I’d been planning to feed to the chickens. But eaten with you, and dollops of fresh jam, it was manna.

I was glad Kaida let you help with the jam instead of taking you up on your kind offer to clean the mold that’s creeping over the Poles. “He uses too much oxygen when he exerts himself,” she murmured to me. “Both of them do. They’re like oxen, honestly.” I could all but see the calculations scrolling behind her worried eyes.

It’s not your fault you have a broad chest, Stuart! Donald can’t help breathing either, though he doesn’t do it as attractively. Donald spent the afternoon in the control room. He wants to go out to his ship, which he says has better radio equipment, but so far Kaida has refused to help with this plan. So Donald plays with dials, curses, and comes up for meals in a dark mood.

As we were cleaning up, Uncle the Computer sang out his happy alarm. The first peacock egg was hatching! We gathered around the incubator to watch the little damp birds fight their way into the world. I made tea. My hand brushed yours when I gave you your teacup, Stuart. Did you notice? I don’t think you did. You spent the whole time scooting closer to Kaida as carefully as a fox stalking a chicken.

Four of the eggs hatched. The chicks have bright black eyes and piping voices. I hope the chickens take to them, and vice versa. I’ll make a Ceremony for it.

Evening.

An unpleasant scene at dinner. After we were all in high spirits from the jam and peacocks!

Well, not all of us. Donald climbed up to Kitchen Level as I was ladling mutton cassoulet onto plates. He announced to no one in particular that our communications array was too primitive to reach Mars. Then he grabbed Kaida by the wrist and yanked her close, growling, “But you know that, huh?”

“Don!” said Stuart. Kaida looked down at her wrist, puzzled. It was such a strange gesture. I used to yank on Kaida’s arm like that when I was a very little girl. Sometimes our guests are curiously childlike.

“Any time we mention going back to the ship, she’s got an answer.” Donald dropped Kaida’s arm and turned on Stuart. “It’s a waste of resources. It’s not the right time. It’s never going to be the right time!”

“Give her a chance to get used to things,” said Stuart. “She’s never known anything but this station.”

“You think you’re doing her any favors?” Donald suddenly remembered Kaida again. “Such a nice guy, huh? Such a saint. Has it gotten him in your pants yet?”

“We can discuss this tomorrow,” said Kaida. “Over breakfast. Eggs and tomatoes.”

“Oh, no. Oh, no no no. Let’s have this out.” Donald turned back to Stuart. “I don’t blame her for putting off the inevitable. She knows what she’s got to look forward to. Her and the little girl.”

I’m not that little.

“It doesn’t have to be that way,” said Stuart.

“Course it does. Dress it up however you want, the hard truth is that we need food and water and women, and we found them here. When we get back to the colony there’ll be a lot of talk, a lot of meetings where everyone pulls sad faces and talks about necessity, but it’ll end the same.”

“It ends with the colony taking the Tower,” said Kaida. Our guests ignored her. She might as well have been a jar of jam.

“Don—” said Stuart again. Poor pained Stuart! You looked absolutely Byronian.

“Am I wrong?” said Donald. “About anything?”

Stuart looked away.

“Didn’t think so.” Donald kicked his chair aside and headed for the door. “It’s the hypocrisy that makes me sick. At least own up to what we’re doing here.” He paused at the door. “Tomorrow we fly home to make our report. The girls can come or not, doesn’t matter. Someone will be back for them.”

We watched him go. Then Kaida sat down and ate her cassoulet. After a pause, I did the same.

“How can you eat after that?” said Stuart.

“We should have started eating half an hour ago. The cassoulet’s a little cold, but it’s still very good.”

“It is, Stuart,” I said. Though your name was more delicious in my mouth than the mutton. “Try it.”

“You don’t understand what’s going on.”

“You want me to go to Mars,” said Kaida.

“I don’t want you to go, I …” Stuart groaned. Kaida smiled patiently, as she used to do when she caught me in a fib but wanted to wait for me to confess on my own.

“I’ll go, of course,” she said.

“Me, too,” I said quickly.

Stuart shook his head. “You don’t know what you’re saying, Kaida. You don’t know what it’s like.”

“Are there really not any women there?” I said.

“We have women. Old, injured, poisoned by radiation. Maybe three are still fertile.”

“But surely they have undamaged cells—”

Kaida laid a hand over mine. “They don’t have our resources, Cat.”

“I’ve got to talk to Don,” said Stuart. “Before he does something rash. I’ve got to make a plan.”

Stuart, did you hear me? I’ll go. I’ll go anywhere with you. Why didn’t you listen? Why did you look past me and see only Kaida?

Although I suppose you didn’t really listen to Kaida, either.

Dawn.

I have been up all night. And you know it, Stuart! You kept me up!

I was on my way to bed when you stopped me in the corridor. “Cat, can we talk? Alone.”

My heart poured out of my breastbone.

We climbed down to Orchid Level. You motioned for me to be quiet as we passed Control Level. Donald was asleep in there, guarding the ship. In the morning he would make Kaida open the airlock—“Or force it open himself,” you muttered.

“Why would he do that?” I said. “We said we’d go.”

“Kaida doesn’t mean that.”

My bare toes touched soil. I can identify every Level in the Tower by the feel of the dirt floor. Orchid Level uses a low-nutrient soil mix, and the ground is rough and grainy, as different from the packed chill of Tundra Level or the soft grass carpet of Wildflower Level as … well, as you are from Donald, dear Stuart. Or as Kaida is from me.

Orchid Level was enchanting in the dark. Around us were fireflies; under our feet were stars. It was as if the Tower were telling me: This is it. Confess your feelings now.

“Don’t you see, Stuart?” I said, glad I’d pulled on my best red wrap. “If you go, I’ll go. If you stay, I’ll stay.”

You poor beautiful fool, you didn’t understand me at all. “It wouldn’t do any good for me to stay. Don will go to the colony, make his report, and be back to plunder this station.”

“What if Donald stays, too? The three of us could hold him. We could put him in—oh, I don’t know, the North Pole, I suppose.”

Kaida would point out that this was fantasy. The Tower was already unbalanced, bleeding resources. They couldn’t stay forever. But in the moment, in the artificial night, it seemed possible.

“Be reasonable, Cat. You can’t imprison a man for life.”

“When Kaida and I go to Mars, will we be imprisoned there?”

“Well … until you get used to the way things are …”

“Why is it reasonable to imprison us, but not Donald? We’d give him books and things.”

“Because you can’t! Honestly, I’m talking to a child.” I was thinking the same thing, Stuart, but don’t hold it against me. I’m fond of you even when you’re silly. “Anyway, Don’s right. Dammit, he’s right. We need this place. We need you. You need us, too, you know.”

“Of course I need you, Stuart.”

You looked straight into my eyes then. I felt more seen than I’d ever been seen before, and I thought, I got through to you. “Can I ask you something?”

“Yes, Stuart?”

“You and Kaida are clones, aren’t you?”

Of all the ways to shatter a mood! I was almost too bewildered to be heartbroken. I adore genetics, but how could you let science distract you from our perfect moment?

I took you up to Taiga Level, which you and Donald hadn’t visited yet. It’s practically a monoculture, just conifers and lichen, churning out oxygen but not doing much to charm. But the chilly temperature makes it a useful place to keep our cryonics. I showed you our seed banks, our embryo banks, all the potential coffee plants and kakapos and slime molds and cats we might someday be able to welcome to the Tower.

Probably never cats, sadly. The Tower can’t handle anything that hunts for sport.

“There’s only one human sample,” I explained. “She should have saved tissue from the others before they died, but she didn’t. It was a long time ago, before people learned how to do Tasks.”

“And since then everyone in this satellite has been the same person.”

“We’re not the same.” But you know that!

I showed you the cells. We keep petri dishes in two separate freezers on Taiga Level and another on Kitchen Level in case something goes wrong on Taiga. Taiga is also where we cultivate the live sample.

“We always have an active cell culture on hand,” I explained. “It’s refreshed and tested for damage regularly.” Cryonics isn’t a perfect science. Remember the eggs that don’t hatch. Remember the seeds that rot instead of sprouting. It’s tragic enough to lose the last mung beans or colobus monkeys, but losing the last human DNA would be the end. The Tower can’t function without us. Uncle the Computer would do his best, bless his artificial heart, but after all he’s only a computer.

Maybe someday the Tower will be balanced so we can take the same measures to protect all the stored genetic material. For now, we can just about protect ours.

“And you just throw out the old … flesh?” You seemed so squeamish about the whole thing. I thought it would be easier to handle than the fish. The petri dishes don’t thrash around.

“We eat it if Uncle tells us to. It’s not very nice. I prefer to give it to the foxes.”

“Good God. Someone needs to save you girls.”

“Oh, petri steaks aren’t that bad. You can always cut them up and put them in a stir-fry.”

“Donald’s right. God, Donald’s right.” You swallowed hard. “Look, this isn’t workable. Even if you’re too young to understand, Kaida’s got to know it. You can’t have a population of just one person repeating forever.”

“Of course you can.”

“And you can’t stay in the Tower! See, you’ve got me calling it that. You can’t live in Hopewell Station forever, never growing, never changing.”

“We change,” I said. “We just do it very slowly. I’ve got a birthday coming up—”

“Kaida’s mother. Was she another clone? Did you eat her too?”

“Kaida and I, yes.”

“Kaida.” I was spoiling your romantic image of my sister. In other circumstances I might have been pleased, but this was all wrong. Why did you get so upset, Stuart? We told you the Tower has to stay in balance. We told you about the Great and Solemn Tasks. You know meat is precious.

“This place is dead,” you told me. How could you say that, with the pine sweet in the cold air? “It’s a coffin.”

“It doesn’t matter, Stuart.” I didn’t want it to matter. “What’s important is us.”

“You don’t know what it means to be human.”

“It means love.”

“It means growth.” You strode through the trees, looking for an exit. “It doesn’t mean spinning in a glass coffin until the end of time. It means growing and reproducing and never giving up. It means spreading across goddamned Creation.”

And that was when I stopped chasing you, Stuart. Not when I stopped loving you. I’m quite sure I’ll always love you. But there’s something wrong with you and Donald. Something unnatural. I only saw it clearly in that moment.

I love genetics almost as much as I love you, and I’ve studied it far too carefully to be mistaken. Unchecked growth isn’t human, not the way we understand it in the Tower.

Unchecked growth is cancer.

The lights are going up all over the tower. Soon, Kaida will wake up, and I’ll explain things to her. Then you’ll wake up, and we’ll all have breakfast. Sooner or later you’ll wonder what happened to Donald, and I’ll have to explain all over again.

I hope you listen. You’re lovely, Stuart, but you ought to listen.

The Fourth Day of Mutton Slaughter, the 98^th Day of Poultry Slaughter, the Eighteenth Day of Fox Slaughter, Afternoon.

Taking a break to write in the middle of a very busy day. We’ve had to kill all the sheep and all the foxes and nearly all the chickens. The foxes were the hardest. Kaida did Rudolf, our favorite, and told me not to watch.

After I finish writing this, I’ll start collecting genetic samples from the cull. Maybe someday the Tower can have sheep and foxes again. It won’t be in my lifetime. We’ll skin the foxes and sheep, pluck the chickens, and prepare the meat for the deepfreeze.

“We’ll have sheepskin blankets,” I said. “Sheepskin rugs, even. It’ll be positively decadent.” But Kaida didn’t laugh, and neither did I.

With the animal population reduced, oxygen levels will rise. In time, the Tower will recover from the imbalance I created by opening the airlocks on Control Level to asphyxiate Donald.

We’ve left Donald there for the moment. We don’t have foxes to feed him to anymore. I bet he tastes nasty.

Stuart is locked on the North Pole. Kaida took him there after I told her what I did to Donald. She says it’s the safest place to put him until we figure out what to do next. The other Levels have too many access shafts he could escape through, too much equipment he could smash if he had a fit.

Please don’t hate me, Stuart. Please eat the food we send up. So far all you’ll take is bread and water, and that can’t be very nice.

I don’t know what Kaida said to get you to the North Pole without asking questions. She says she’ll tell me when I’m older. I hate being young!

Sometimes I think if I were older it wouldn’t have come to this. Stuart and I would have fallen in love and worked out some perfect solution. Maybe we could have gone to Mars together, and left Kaida behind, and sworn a sacred vow never to reveal the location of the Tower. Then everyone could have lived happily ever after (except Donald, I suppose, because he wouldn’t respect a sacred vow) and the Tower would be safe.

But in my stomach I know that’s not true. Even if I were older, even if I were the one with the talent for math, I could never rebalance the equations that decide how many people can come to the Tower, and how many can leave, and how many can live.

“We can’t let them tell their colony about us,” I told Kaida last night. “These aren’t normal people. They’ll eat the Tower. They’ll eat and eat and they won’t stop for anything. It’ll be like a bone with the marrow sucked out.”

Perhaps I was raving. I’m sure I looked wild. I look wilder now. There’s been so much blood.

Kaida placed a cool hand on my head. Then she told me to go to sleep. She combed her hair, pulled on her best robe, and padded down the corridor to Stuart’s apartment.

She didn’t tell me whether I did the right thing. Right now, looking at the piles of slaughtered animals, I don’t know.

Night.

It might have been the silence that woke me up. I’d gotten used to the faint sounds of our guests down the corridor. One of them snored a lot. I suppose I’ll never know which one. But I awoke a little while ago to nothing but the pulsing of air vents and the steady hum of electricity, comforting as a heartbeat. I was alone on Quarter Level.

Kaida wasn’t there.

I strapped on an air mask and the small emergency oxygen tank by my bed. I climbed down to Control Level. Uncle turned on the lights for me.

Donald was still there, slumped before the security monitors. I turned his seat around so he wasn’t looking at me. His expression wasn’t very nice. I wondered if he used to watch us on the monitors. The thought made me uncomfortable, even though I couldn’t imagine what we did that would be interesting to watch.

I looked at the monitors.

Kaida was outside the entrance to the North Pole. I almost didn’t spot her. She was slumped against the door, looking small. Kaida had never been small to me. Her mouth was moving.

For some reason I hesitated before turning on the sound.

I heard you plead and promise and make offers, Stuart. I heard her cry. Kaida has never cried from sadness before. For dramatic effect, sometimes. It was after you said, “Let me out. I’ll stay in the Tower. I’ll never contact Mars. We’ll make a life here, the two of us.”

She cried because you were lying. Even through the grainy monitor I could tell you didn’t mean it, that things were damaged beyond repair. Kaida couldn’t see you, but you were waiting for her with the machete we use to trim the fir trees. It’s all right. I know you were scared.

Kaida only cried for a minute or so. Then she said, “It’s no good, Stuart. The Tower isn’t balanced for three people. You can’t stay, and we can’t let you leave.”

“Catherine,” you said. “We don’t need Catherine.”

“You want me to cull my sister?” I was flattered that Kaida sounded shocked, even if it was a little overdramatic of her. Everyone has to be culled sooner or later. Our mother culled herself when I got big enough to jeopardize the balance. I don’t remember it, but Kaida says her Ceremony was gorgeous.

“She’s not your sister. She’s … a copy. An extra. She’s the same as you.”

Oh, Stuart. I understand why you lie. It’s your own kind of Ceremony. If we didn’t make Ceremonies to add beauty and meaning to our work, the ugliness of survival would be laid bare, and human beings can’t take that without becoming ugly ourselves. You make up stories about what you’re doing, you imagine coming for Kaida like bold Sir Lancelot and living happily ever after, and it covers up the ugliness a little. Donald refused to lie, he turned ugly, and then he died.

All the same, you don’t need to make your lies quite so obvious. Or so cruel.

“Are you going to kill me?” you said.

“No. I can’t. I love you.”

“I love you, too,” you told her. I think that much was the truth.

Stuart, you beautiful liar. If you really believed I was the same as Kaida, you’d love me.

But you don’t.

I had to leave. My oxygen tank was nearly empty. I put an extra comforter on the bed and crawled in with double socks on. Control Level had been so cold.

As I was writing this, Kaida came in. “I can’t kill him, Cat. I can’t kill him and I can’t let him go.”

“You could do what I did to Donald—”

“No. Anyway, we can’t spare the oxygen.” She buried her head in her arms. “What are we going to do?”

I held her.

“Love is hard,” she said.

“I know,” I told her.

Cat’s Fourteenth Birthday.

My birthday at last! I have a perfect Ceremony planned. We will put on white sandals and adorn ourselves in colored glass of blue and red and crystal, and we’ll perform a dance of my invention. Kaida will make strawberry shortcake.

But first we have to clean up the mess you left on the North Pole, Stuart. You were not a considerate guest near the end. I don’t blame you, but some of the things you did were extremely unhygienic. Kaida insists on cleaning the feces off the walls herself, it being my birthday, and I’m sure you wouldn’t have wanted to make Kaida do that. I’ll do my best to get the algae tanks in working order.

There’s spoiled food strewn all over the place. You really were suspicious of the food we sent. I suppose it was sensible to suspect poison and stick to bread and water. But you didn’t have to throw our cooking around. There are two entire roast chickens I’ll have to fish out of the algae tanks.

You shredded the giant water lilies. Poor things.

Anyway, this morning I poisoned the bread. It was my birthday present. An original strain of Claviceps purpurea, the ergot fungus, which grows on rye. The lysergic acid produced by my breed of Claviceps causes pleasant hallucinations before the onset of paralysis and death. I tried to make you happy.

We watched you on the monitors until you went still. Then I opened the door to the North Pole. Kaida stared for a long time.

“I took care of it, Kaida,” I said. “Wish me happy birthday.”

After a while, she picked up the fallen machete and got to work.

I write this from inside a drained algae pool. It is a different perspective to be sure. Fourteen will be hard. It will take so much work to balance the Tower. At least we have plenty of protein in the deepfreeze to keep us going. Our poor foxes! And now there are three human gene samples on Taiga Level.

Someday, not soon, but when the balance is right, there will be another birthday. I’m sure I’ll want to incubate the embryo myself, but I haven’t decided whether to clone you directly or mix our DNA to create a new genotype. I have plenty of time to think it over. Uncle the Computer won’t let us have another girl in the tower, even a very little one, for thousands of days.

Kaida has already told me her next birthday present will be a secure holding cell and saferoom on Control Level. A good idea, but not very exciting. You know how Kaida is.

I miss you, Stuart. But I’ll see you, or part of you, again. Until then I’ll wish it on every star and plan it on every birthday.

I love you. I love you. I love you.

Come home.