I

When the kettle on the induction hob gave its first whistle, Chen Mo laid his left hand on the scalding handle, held it there for two seconds, and only then drew it back.

It was the fourteenth gesture Zhou Sheng had taught him. According to the story Zhou Sheng left behind, he had suffered a mild stroke at sixty-five, and ever since, pain had reached the left side of his body half a beat late; he only remembered to let go once the red mark was already there.

The cooling fan of the old hob droned. Steam rolled against the yellowed tiles on the wall, beaded into fine drops and ran down the grout. The flat smelled of dried tangerine peel simmered all night, mixed with old camphor wood. To get that smell right, Chen Mo had moved in three days early, sealed the doors and windows, and slow-boiled four ounces of aged Xinhui peel over a low flame.

Beyond the frosted glass door of the kitchen, a shadow shifted, very slowly.

Chen Mo did not turn around. As the rules required, he wore the dark grey wool cardigan Zhou Sheng had left behind, its collar pilled where stubble had rubbed it, the sleeves rolled up twice to show an old mechanical watch on his wrist. A scratch ran diagonally across the crystal. The hands said half past six on a morning in 2072, but the gears behind the date window had long since been forced to a stop on a day in October, forty years ago.

"You're up?" Chen Mo kept his back to the door and pressed his voice deep down in his throat. The micro-damping patch on his vocal cords gave it a breathy rasp, like a bellows, like a man just out of sleep. "There's warm water on the table. Don't go looking out the window yet. The doctor says the swelling in your retinas hasn't gone down."

No answer came from behind him.

A full half-minute passed before he heard slippers on the wooden floor, very faint: two steps, a pause, another step, like someone feeling their way across a frozen river in the dark.

It was what every sleeper went through on leaving the pod. A person who had lain forty-two years in liquid nitrogen at minus 196 degrees, in a low-metabolism capsule, had lost a fifth of their bone density even after forty-eight hours of graded rewarming. The stones of the inner ear had not yet settled back into place; the soles of the feet felt as if they were treading on cotton, and gravity seemed twice as heavy as it had been before sleep.

The glass door slid half open, its hinge giving a stiff little creak. Lin Xin stood there, holding on to the frame.

She looked no more than twenty-eight. Over her hospital gown she wore a man's old jacket, washed pale and plainly two sizes too big. Her hair had been cut to her earlobes when they peeled the neural electrodes away, and her face was the colour of candle wax kept long out of the light, her lips without a trace of blood. Only her eyes, under a thin film of cloud, were frighteningly bright. They were fixed on the slight stoop of Chen Mo's back, and on the hair at his temples, which he had dyed white and blow-dried on purpose.

The spoon in Chen Mo's hand kept stirring the oats, steady. From the corner of his eye he could see the micro-patch at the base of his right forefinger. It was talking in real time to the subdermal chip in the side of Lin Xin's neck. Green light. Heart rate seventy-four. Cortisol normal.

Inside, he let out a long breath. The most dangerous hurdle, the first opening of the eyes, was behind them.

II

In the files of the Dormancy Bureau, Chen Mo's job was called a "decompression stand-in."

Humanity had invented sleep across the decades. It had learned to seal the incurable into time like hibernating frogs. What it had not managed to rewrite was the brain's oldest defences. In the early years, the first sleepers to lie half a century were simply woken. They walked out of the hospital gates to find two orbital elevators driven up into the stratosphere, streets full of slang they could not follow, and the person they had kissed goodbye only yesterday reduced to a handful of ash. More than four in ten died within seventy-two hours, of brainstem haemorrhages brought on by acute stress.

The brain cannot take a cliff in time. It needs a slope.

And so the Seven-Day Landing Period was born. Before a sleeper woke, the Bureau would rent a single-storey house in the old-town conservation zone, one that still kept the fittings of a bygone age. Every modern network signal was cut off. A relative was assigned to keep the sleeper company for seven days, breaking forty years of change into crumbs and feeding them a little each day.

But there were always families who swore they would live to see the sleeper wake, and then did not make it through the last two or three years of the countdown.

Under the Bureau's supplementary regulations, once a sleeper was classed as an "unanchored orphan" and showed severe stress reactions in the first days after waking, they were sent by compulsion to a public Institute of Psychological Reconstruction for six months of "emotional pruning": targeted drugs that dulled the synapses in the hippocampus holding memories of a former partner, so that the sleeper could walk into the new society safe and compliant, like a negative washed clean. It was to escape this clause that Zhou Sheng sought out Chen Mo, in the dead of winter in 2070.

Lin Xin was nineteen months from thawing.

Chen Mo still remembered the first time he saw Zhou Sheng, in a draughty teahouse in the Grey Zone. The old man was as thin as a bundle of dry kindling stuffed into an old overcoat, badly hunched, and every three sentences he pressed a dingy handkerchief to his mouth and coughed until he folded in on himself. He had not gone through the Bureau's official assignment channels. He had emptied his savings and searched in private for half a year before he settled on Chen Mo, a man who did not like to talk, and whose back was nine-tenths a match for his own.

"I'm not going to make it." Zhou Sheng pushed a stack of notebooks bound with a rubber band across the table. They were crammed with forty years of prices and news, down to the dates on which the pothos plant at home had died. "Lin Xin looks mild, but she has a fierce temper. If the first thing she sees when she opens her eyes is a death certificate, or if she finds out the Bureau means to wash her mind, she'd sooner beat her head against the wall than get past the third day. You're built like me. Meet her for me. Just seven days. Keep her readings in the green, get her the release-at-liberty permit, then tell her I've only just gone."

For the eleven months that followed, Chen Mo lived in the attic Zhou Sheng rented beside the last tram stop.

As if learning a dying dialect, he fitted himself, inch by inch, into Zhou Sheng's shell: the faint tremor when he held a spoon in his left hand, the habit of pushing his reading glasses up onto his forehead to read the paper, the soft grinding his right knee made from an old injury when he walked on rainy days.

Zhou Sheng was a teacher strict to the point of obsession. If Chen Mo broke an apple peel even once, the old man would snatch the knife and, breathing hard, show him himself: the blade against the flesh at fifteen degrees, the right thumb set firmly on the stem, all in one movement, and the whole peel had to come away without a single break.

"She likes them crisp. She doesn't like the skin." Zhou Sheng handed Chen Mo the bare, gleaming apple, lit one of his three-yuan-a-pack hand-rolled cigarettes, and hid under the narrow extractor fan in the kitchen to take two fierce drags, then flapped at the smoke in a panic with a damp towel. "Remember: if she asks, I gave up smoking at thirty-five. She has a sharp nose. She hates the smell of smoke."

Watching Zhou Sheng's hands on the fruit knife, Chen Mo had his doubts even then.

Zhou Sheng was left-handed, and a short joint was missing from the ring finger of his left hand, the stump a smooth round knob of flesh. Yet when he demonstrated the apple, Zhou Sheng used his right. Chen Mo asked him: "Should I tape up my left ring finger with skin-coloured tape?"

Zhou Sheng only waved the idea away, his eyes on the grey snow outside the window. "Don't bother with any of that fuss. People fresh out of the pod have ice-fog blindness. They see double. She won't be staring at your fingers. Just get the back and the voice right."

Eleven months and four days in, a cold wave swept across the north, and Zhou Sheng stopped breathing in his sleep.

Before he died the old man had told him: once he was cremated, the tin biscuit box full of cigarette ends by his bed was to be thrown into the sea, and on no account taken into the landing house. Chen Mo gave him a simple funeral and collected the balance of his fee. He washed the dark grey cardigan Zhou Sheng had left, dried it in the sun, and laid it for half a year in a camphor-wood chest full of old books, until every fibre had soaked up the old man's smell. Only, for no reason he could name, he did not throw away the tin biscuit box. He locked it in the false bottom of the toolbox he carried everywhere.

III

For the first three days of the landing period, the house was as quiet as a clockmaker's shop sunk to the bottom of the sea.

Chen Mo followed the Bureau's Graduated Disclosure Protocol to the letter, and kept a constant guard against the wide-angle assessment camera set into the ceiling lamp in the living room. The Bureau's back-end algorithms watched the picture and listened to the ambient sound of the house around the clock. The moment they judged that a sleeper had seen through the stand-in, or that the heart rate had crossed the red line at one hundred and forty, the medical intervention van stationed two blocks away would break the door down within three minutes.

On the first day, every blind in the house stayed drawn, and only the yellow lamps were on. Chen Mo seldom turned to face Lin Xin directly. Most of the time he sat in the rattan chair on the balcony reading old newspapers, leaving her an old, quiet profile. Lin Xin rarely spoke either. She sat at the dining table with the blue-rimmed enamel mug in both hands, a whole afternoon at a stretch, her gaze resting on Chen Mo's rolled-up sleeves and his slightly lame right leg.

The only anomaly came at two in the morning, on the first night.

Chen Mo was asleep on the folding camp bed in the living room when, half dreaming, he heard water running hard in the bathroom at the end of the corridor. He jolted awake and looked down at the bio-patch on his wrist.

The light, green a moment ago, was flashing a frantic orange-red alarm.

In three seconds Lin Xin's heart rate had leapt from sixty-two to one hundred and thirty-eight, two beats short of the red line that would bring the medical team through the door.

Chen Mo's own heart stopped for an instant. He rolled off the bed, and his hand had just found the bathroom door handle, before he could even knock, when the red light on his wrist suddenly went out. One hundred and twenty. Ninety-eight. Seventy-six. Sixty-five. In under ten seconds that frighteningly steep curve was shoved back underwater, as if by some unseen hand, and lay flat again, still as dead water.

In the bathroom, the tap shut off. Lin Xin opened the door and came out, her short fringe wet and stuck to her cheeks, her face three shades paler than in the day. She glanced at Chen Mo, so calm she was almost cold: "Bad dream. I washed my face."

Chen Mo watched her walk back to the bedroom, then went into the bathroom and looked around. There was water on the mirror. The sink was clean. Nothing out of place. He took it for the neural reflex spasms common in sleepers and thought no more about it.

The second and third days went as smoothly as a play rehearsed a hundred times.

On the afternoon of the second day an autumn rain set in. Crossing the living room to close the window, Chen Mo stopped, naturally, and rubbed his lame right knee with his right hand. Lin Xin was on the sofa knitting an old scarf half begun, and asked without looking up: "Still hurts when it's overcast?"

"Old trouble." Chen Mo answered from page seven of the notebook. "Big snow in the winter of fifty-eight. I slipped. Didn't crack the bone, just caught a chill in the tendon."

On the evening of the third day the rain stopped. As planned, Chen Mo "accidentally" pulled up half a blind.

The low sun slanted in. Above the skyline hung an extremely fine band of silver light: the equatorial geosynchronous orbital ring, completed in 2054.

Lin Xin stood at the window. Her pupils shrank sharply. The monitor patch on Chen Mo's wrist jumped at once to a glaring yellow: heart rate one hundred and twelve.

Chen Mo went straight over. He did not touch her, only stood half a step behind her and spoke in Zhou Sheng's slow, sandpapery voice: "Don't be scared. That's the solar ring they built in fifty-four. When it was new it was so bright at night you couldn't sleep. I wrote a letter of complaint to the city about it. No use. Then you get used to it. Saves turning on a light when you get up in the night."

To shrink a seismic shift of the age into a commonplace grumble: that was standard language from the decompression manual.

Lin Xin's fingers, clenched on the curtain, slowly let go, and the yellow light on the wrist dropped back to green. She looked down at the back of her own hand, absurdly young, and asked quietly, "Back then... you lived on your own?"

"Mm. When I retired from the mine I rented a one-room place here. Close to the dormancy centre. On Sundays I could go and wipe down your pod door." Chen Mo recited from page three. "The rent went up once, in fifty-eight. I nearly moved out to the northern suburbs. Then the landlord saw how old I was and let me off the odd change."

Lin Xin nodded, gave him a look through the dim dusk, and asked nothing more.

IV

By the fourth day, according to the rules, Chen Mo should have been laying the groundwork for the excuse: Zhou Sheng's health was poor, in a couple of days he would be moving into a sanatorium for good. That way the goodbye on the seventh day would follow naturally.

For dinner that day Chen Mo stewed winter melon and pork rib soup. Zhou Sheng had circled it in red in his notes: after fifty his sense of taste had gone badly, he always salted his food heavily, and the soup took two and a half level spoons of salt. Chen Mo did it to the gram, tasted a little himself, and the salt was so strong it made the root of his tongue bitter.

Lin Xin ladled herself a bowl and took a sip. Her brows drew together, almost imperceptibly, then smoothed again, and without a word she drank the whole bitter, salty bowl down to the bottom.

While he was clearing the dishes, Lin Xin did not go back to the bedroom as she had on the other days. She leaned against the kitchen doorway and suddenly said, "Peel me an apple."

"All right." Chen Mo turned into the kitchen.

"Turn on the extractor fan," said Lin Xin, following him into the narrow kitchen and pulling the frosted glass door shut behind her. "It's stuffy in here."

Chen Mo thought nothing of it and pressed the switch on the wall. The ancient cast-iron fan started up with a thunderous roar, its blades setting the sheet metal of the duct rattling and shaking. Sixty-odd decibels of low-frequency noise filled the tiny kitchen, less than four square metres, in an instant, and shut out every sound from the living room beyond.

Chen Mo picked a Fuji apple from the fruit basket and took up the well-honed fruit knife.

Inside the roar of the fan he set his thumb on the stem and turned the apple with a steady wrist, once round, twice round, the deep red peel hanging between his fingers like an unbroken ribbon, until the last of the stem was flicked free and dropped into the bin with a soft tap.

He held out the white, naked apple. "Here. A crisp one."

Lin Xin did not take it.

She raised her head, and those eyes, the swelling gone now, clear as a cold, deep pool, looked straight into his. For the first time in four days she was close enough to see the traces of silicone shaping on his face, and the clarity behind his eyes that did not belong to a man of seventy.

"Zhou Sheng never peeled an apple in one piece in his life." Lin Xin's voice was very soft; under cover of the fan's roar it settled on the counter like a feather. "He was clumsy. He'd break one apple's peel into seven or eight bits and leave the flesh all gouged and pitted, and in the end he couldn't be bothered and always just rinsed it under the tap and ate it skin and all. When I was twenty-five I laughed at him for it, and he sulked and told me that when he was old, seventy, and his hands were steady, he'd peel me one without breaking the skin."

Chen Mo stood frozen where he was. A cold sweat broke across his back. By reflex he looked down at his wrist. If Lin Xin had just found out that the husband in front of her was a fake, the cliff in time would swallow her whole, the monitor would sound, and the medical team outside would come through the door within thirty seconds and push a heavy sedative into her.

But the patch on his wrist glowed a quiet green. Heart rate sixty-eight, calmer even than when she had been drinking the soup.

Lin Xin reached out, took the flawlessly peeled apple, bit off a small piece and chewed it slowly.

"The first morning, you touched the kettle with your left hand and waited two seconds before you let go." She was watching the sky darken outside the window, her tone like someone chatting about another family's affairs. "Zhou Sheng was left-handed, but when he was twenty, working at the shipyard, a punch press took off half of his left ring finger. Your ring finger is whole."

Chen Mo's throat moved. The emergency plan he had memorised crashed into a tangle in his head. "Ms Lin, please, don't get worked up. There's surveillance out there. If your heart rate crosses the line..."

"I know there's surveillance out there. Why else would I have asked you to turn on the fan?" Lin Xin cut him off.

She raised her right hand and, unhurried, pushed the sleeve of the big old jacket up her arm, baring a pale, thin left forearm.

Chen Mo drew a sharp breath. On the skin of the inner forearm were two rows of deep purple tooth marks, already scabbed with blood. The wounds went down into the flesh; all around them the skin was blue and black.

"The first night, at two o'clock, while you were asleep, I came out and looked at your hands, and I knew he was gone." Lin Xin pulled the sleeve back down over the terrible wound. "Before I left the pod, the head nurse warned me on the quiet: if my family were gone, the Bureau would send a stand-in, and if my heart rate broke one hundred and forty, I'd be dragged off to the reconstruction institute to have my memories washed out. That night in the bathroom my heart was about to break my ribs. I put my head under the cold water and bit my own arm as hard as I could, used the pain to push the heart rate down, and held the alarm off by two beats."

She raised her eyes. They were threaded with fine red veins, and not a single tear: "I didn't sleep for forty-two years to wake up and forget him completely. The fan's on now. The microphone in the living room can't hear us. Tell me honestly. When did he go?"

V

Chen Mo leaned back against the cold tiles. A long while passed before he reached up and tore off the damping patch on his throat, the one that bit so painfully into his neck.

He let go of the bellows rasp he had been pressing into his throat. His shoulders sagged, and he spoke again in his own voice, a man in his forties: "...Last November. Pulmonary fibrosis, and heart failure on top of it. He didn't suffer at the end."

Lin Xin bowed her head. Her fingers closed hard around the apple, the knuckles white. The patch on the wrist flashed yellow once, the heart rate jumped to one hundred and five, but she forced it back under eighty almost at once. It was a long time, so long that Chen Mo thought she would hurl the apple at him, before she only wiped the corner of her mouth with her sleeve and said: "Yesterday, in the rain, you rubbed your right knee. When Zhou Sheng came off his motorbike at twenty-six, it was his left leg he hurt. And the soup. Did he teach you to put all that salt in it too?"

"He said he was old. He couldn't taste anything, so he always over-salted."

"He lied to you." Lin Xin's mouth twitched, but the smile never reached her eyes. "That man was more afraid of bitter than anyone, and of salty too. If I put one grain too much salt in a dish, he'd drink two glasses of water to rinse his mouth. He would never have peeled an apple with his right hand, either. He taught you all of it backwards on purpose, because he was afraid you'd play him too well and actually fool me."

Chen Mo stared at her. "But didn't he hire me to keep it from you?"

"He hired you to keep it from the Bureau's machines, for me." Lin Xin leaned back against the fridge door and looked up at the fan humming over their heads. "He knew my temper better than anyone. If he'd found someone to copy him perfectly, his clumsy hands, his missing finger, then on the seventh day, when the truth came out, I'd have found I'd spent seven days treating a stranger as my husband, and that would have finished me on the spot. So he gave you a false ledger and hid our signals in the flaws. Two and a half spoons of salt, because the taste buds on my tongue hadn't woken up yet, I couldn't have tasted anything milder, and he was afraid that if he just told me, I'd cry. The apple without a break in the peel: that was the bet he'd owed me for forty-two years. And this deafening fan: when we were first married and rented a basement, it was our trick for hiding from the landlord that we were cooking noodles on the sly."

Chen Mo thought of the bony old man in the attic. He thought of Zhou Sheng coughing as if his chest would tear apart while he made him peel the apple in one unbroken strip. He thought of Zhou Sheng writing in the notebook, stroke by careful stroke, I gave up smoking at thirty-five.

In the last eleven months of his life, with a back like his own and a cardigan steeped in the smell of camphor, that old man had fooled the Bureau's cold cameras. And with a notebook full of absurd "flaws," he had reached across forty-two years and the line between the living and the dead and, on the very first morning, borrowed Chen Mo's hand to knock on a door that only Lin Xin could hear: This isn't me, but I've laid the road for you. Let's play these seven days through together.

"If you saw it on the first day, why did you keep me on?" Chen Mo asked, his voice hoarse.

Lin Xin put the apple core down on a plate and looked up at the pilled, dark grey cardigan on Chen Mo's shoulders. "When you're quiet, sitting out on the balcony, your back looks exactly the way I imagined he'd look when he was old. I wanted to see how he spent these last forty years. Even if it was you acting it out for me, in your body."

For the next two days every rule in the house fell apart, while under the camera everything kept its surface order.

The moment they stepped out of the kitchen and faced the wide-angle lens in the living room, they were a husband and wife who treated each other with courteous respect. But whenever it was time to cook, the two of them would go into the kitchen one after the other, draw the glass door shut, switch on the deafening fan, and take apart, piece by piece, the lies the old man had left behind.

"He says that in fifty-eight the landlord saw how old he was and let him off the odd change on the rent." On the afternoon of the fifth day Lin Xin was leafing through the stack of rubber-banded notebooks, and pointed to a line. "Is that true?"

Chen Mo was wiping down the stove. He stopped. "No. In fifty-eight the mine shut down and his pension stopped. He went and worked the night gate at a freight depot in the northern suburbs. The room there had no heating. That's where he wrecked his right knee, and why he moved back. That's why he had me rub the right knee. For the second half of his life, his right leg hurt more than his left."

Lin Xin's finger rested on the page for a long time before she turned it. "And the pothos? He says he kept it forty years and repotted it three times."

"It died eleven times," Chen Mo confessed. "He had no idea how to look after plants. Every time it was nearly drowned he'd carry it to the flower market and swap it for one that looked about the same. This one I bought for him last week."

Lin Xin burst out laughing. And as she laughed, tears fell onto the yellowed pages of the notebook, spreading into dark round spots.

The monitor on the wrist jumped to ninety-five, but did not cross the red line. This time the tearing pain of time did not come. The tears had soaked the forty-year cliff soft.

VI

On the night of the sixth day a typhoon grazed the coastline, and outside the rain came down in sheets.

After dinner Lin Xin carried the notebooks into the kitchen and turned to the strangest pages, in the middle.

"Mr Chen," she said under the roar of the fan, pointing at a gap in the notebooks three years long. From 2048 to 2051 there was not a single word. And from 2051 on, the neat, elegant left-handed pen script turned suddenly into a crooked, laborious right-handed hand. "These three years, where did he go? Why did he switch to writing with his right hand afterwards?"

Chen Mo was silent for a moment. "He told me he spent those three years in the lithium mines in South America saving up the dormancy tax. Then the stroke at sixty-five, his left hand stopped working properly, and he changed to his right."

"He lied to you about that too." Lin Xin shook her head. Her fingers brushed over the stiff strokes, like a child tracing characters over a copybook, and a bottomless sorrow showed in her eyes. "Before I went to sleep, the dormancy tax was already paid for twenty years. And what I had was severe myelodysplasia. The doctors said plainly that a targeted gene therapy would be on the market within fifteen years at most. By rights I should have woken in 2045. These past few days I haven't dared to ask you: why did I sleep twenty-seven years longer?"

Chen Mo stood stunned. Of this, Zhou Sheng's notebooks said not one word.

He looked at Lin Xin's white face and suddenly thought of the tin biscuit box he had kept in secret in the false bottom of his toolbox. He went out of the kitchen, took the rusty tin from his own room, and prised off the lid in front of her.

Inside were half a box of cheap, unsmoked cigarettes and an ashtray made from an old jam jar. And in a cardboard sleeve under the jar, two yellowed documents folded into neat squares.

Lin Xin drew them out with trembling hands and unfolded them under the greasy yellow light. On top was a Sleeper Revival Risk Notice dated 2045. Beneath it, a red-stamped Labour Contract for High-Risk Maintenance Work on Cryogenic Lines.

The type on the notice had begun to fade, but a line of small print in the conclusion box was still clear, and cut the eye:

MRI review, April 2045: owing to the limits of first-generation cryoprotectant technology of the early 2030s, the patient in Pod No. 3 (Lin Xin) presents a risk of micron-scale ice crystals at the margins of the hippocampus. If thawed under current methods, the targeted therapy can cure the primary disease, but there is an 83% probability of irreversible retrograde amnesia (permanent loss of all personal memories prior to dormancy). Lossless nano de-crystallisation technology is expected to mature around 2070. It is recommended that the patient be transferred to a zero-degradation special maintenance pod for extended dormancy. Note: the transfer and twenty-seven years of special maintenance fees are to be paid in full at the family's own expense...

In the kitchen there was only the fan's monotonous howl.

Lin Xin held the thin sheet of paper, and as if the bones had been drawn out of her, slid little by little down the fridge door until she was sitting on the floor.

Every piece, in that moment, fitted together without a seam.

In 2045, the targeted therapy really had come out. Zhou Sheng, barely past forty, ran to the dormancy centre overjoyed to bring his girl home, and at the signing desk he was told: if you wake her now, she will live, she can walk the rest of your life with you, but when she opens her eyes she will not remember who you are. If you let her sleep on until 2072, she can wake whole, with every memory she has. Only, by then, you will most likely be gone.

Standing in a corridor in 2045, Zhou Sheng chose the second for her.

To raise the astronomical fees for the special maintenance pod, he never went to any lithium mine in South America. He signed on for the most dangerous work the dormancy centre had, maintaining the cryogenic lines deep underground, and every day he crawled into the cavities around the liquid-nitrogen mains at more than a hundred degrees below zero to service the valves, keeping watch directly beneath her pod.

Chen Mo looked at the record of industrial injuries at the end of the labour contract, and his throat felt stuffed with cotton soaked in vinegar:

November 2048. Rupture of a liquid-nitrogen branch line, Zone B, Basement Level 3. To protect the power circuit of the special maintenance pods above, maintenance worker Zhou Sheng closed the minus-190-degree shut-off valve by hand, sustaining severe frostbite to the left hand and forearm. The limb was saved, but the left ulnar nerve and pain nerves are permanently dead.

There had never been any stroke at sixty-five.

He had taught Chen Mo to rest his left hand on the scalding kettle handle for two seconds because, from that winter in 2048 on, his left hand could no longer feel the cold, or any pain.

"He never gave up smoking either." Chen Mo crouched and set the tin box of cigarette ends on the floor, his voice rough. "Every night at two, his lungs hurt too much to sleep, and he'd hide under the extractor fan in the attic and smoke half a cigarette. Afterwards he'd flap a wet towel about for ages, afraid the smoke would get into the cardigan he was saving for you."

Lin Xin sat on the cold tiles, picked up a cigarette, and raised it to her nose. Cheap tobacco and a faint mustiness of damp; it caught in her throat and she coughed softly. Then she buried her face deep in the pilled dark grey cardigan, bit down hard on her lip and swallowed every sob, until all that escaped between her teeth was a whimper, again and again, like a young animal's.

Late that night the rain stopped. Lin Xin did not light the cigarette. She only held it between her fingers the way Chen Mo had described, slumped sideways in the rattan chair on the balcony, and looked up at the silver orbital ring arched across the night sky.

"It's so bright," she said. "Much brighter than the moon used to be."

"Mm. You get used to it." Chen Mo stood beside her, the way he had once stood beside Zhou Sheng, and kept the night wind off the sea from reaching her.

VII

At half past six on the morning of the seventh day, the Bureau's white car pulled up outside the gate, on time.

The landing period was over. The assessment report read: all neural indicators stable; no generational shock; emotional pruning not required; cleared for entry into social life.

Chen Mo changed back into his own dark jacket. He folded the dark grey cardigan neatly, laid it on the dining table, and set the fruit knife on top.

Lin Xin had already changed into the clothes of 2072: a light, thermo-regulating trench coat, sharply cut, that made her look like a student just out of university. She stood in the hallway holding a very small suitcase. In it were only the stack of notebooks full of lies and the tin biscuit box full of cigarette ends.

Before she went out, she crossed to the dining table and picked up the old watch whose calendar had stopped forty years ago, and fastened it on her slender left wrist. She caught the rusty crown with her fingernail, pulled it out one notch, and pressed it hard back in.

From inside the case came a faint click. The calendar gears, jammed for forty-two years, caught again and began to move forward.

"Mr Chen." At the door Lin Xin suddenly stopped and looked back at him. "The last gesture he taught you before he went. What was it?"

Chen Mo thought about it.

It was early autumn in 2071. Zhou Sheng could no longer get out of bed. He had wasted to a handful of bones, the back of his right hand all bruised blue and purple from needles, his numb left hand lying quiet on top of the covers. The sun was lovely that afternoon. Chen Mo was on his way out to buy groceries when the old man called him back, and with great effort lifted his right hand and gave one faint wave in the air; then he drew the palm back and patted his own chest, gently, twice.

"He had no strength left to speak." Chen Mo stood in the light and shadow of the hallway and, facing Lin Xin, made the gesture exactly as it had been made: raise the hand, one wave, draw the palm back, two soft pats on the chest. "I didn't understand it then. I thought his chest felt tight. I called the doctor."

Lin Xin watched him, and for two seconds did not move. Then her lips began to tremble violently.

"When we were first married," she said, lifting her own hand and, across forty-two years, patting her chest twice, gently, as the tears at last ran down without restraint, "every time he saw me onto the early bus for my shift, we couldn't hear each other through the window. He'd pat his chest twice. It meant: I've got this. Go, and don't worry."

Outside in the yard, a horn sounded twice, impatient.

Lin Xin drew a deep breath, wiped the tears from her face, turned, and pushed the front door open.

The October sun poured in unchecked and lit the specks of dust drifting in the air. She took a step forward. Her feet came down steady on the hard concrete of 2072. She did not sway again, and she did not look back.