Lys aged four made her first memory, crying at her Gran's house. She cried with furious desperation because Gran had taken her to the zoo and Lys very much didn't want to forget the delicate jellyfish and the huge graceful giraffes. But her Gran tucked her up in bed, patted her bobbed brown hair, and wouldn't listen to Lys make her record ("You don't have to tell me about it! I was there, petal.").
       Lys fell asleep knowing the animals would all be lost.
       But the next day, she could still remember them.
       How?

       Lys aged six was always in motion, shuttling between her Gran's house and the research base where her parents lived and worked.
       She stumbled over the many differences. At Gran's, Lys went to school and church and took trips to the bright white beach. There were fresh lychees, and Lys had to wear a dress on Sundays. At the research base, everyone wore the same jersey suits; everyone ate the same food packs in the mess. Eating and undressing both involved peeling off beige wrappings.
       The base itself consisted of four long metal corridors, with many identical doors, most of them out of bounds -- no fun for exploring. But outside the base, wonderous blue rocks stretched in every direction, and Mum and Dad took Lys for walks through the dim cobalt air.
       You could jump for metres because you weighed so little. Lys tried that on the beach at Gran's and sprained an ankle.
       Gran liked Lys to hold onto her hand when outside, but when Lys tried to hold onto Dad, he said: "What's wrong, can you not stand up? Got sea legs?" And Mum said: "Every holiday you get bigger, darling, and one day you'll knock me over."
       The chief difference between the base and Gran's house came at bedtime. On the base, Lys told Mum and Dad the things that had happened that day, and they took a record, which somehow went down to the Historians. At Gran's, there were stories before bed. She told them to Lys. Lys didn't say anything to her, and you didn't need to keep a record (which was why Lys could still remember the wonderful day at the zoo).
       The record only partially pinned things down, though, and events escaped it, slipping both forwards and backwards. Intrusions happened all the time, at the base. They looked real, but they weren't. Mum said it was polite to ignore them. Mum said Lys needn't worry, because they might never happen. When Lys repeated that to Gran, Gran pursed her lips ("What are they showing you, up there?"). Lys found it hard to remember that everything at Gran's house was real, and happened once only.
       Back and forth Lys went, making mistakes at each end of the journey. One night at her Gran's, she looked her misery in the face: she was slow, a difficulty, a bother. She was wrong in a way that went beyond confusing two kinds of cutlery, or two strengths of gravity. But nobody seemed willing, or able, to guide her.
       For comfort, Lys held the blue rock she'd found outside the base. "A paperweight!" Mum had said. Lys loved the stone for its domed top, too big to grip, and flinty rippled underside. Holding it in both hands, Lys resolved to work out for herself how to live in two worlds.
       She decided that as soon as she was back at the base, she would ask the Historians.

       The dim rich air stroked Lys's skin as she skipped across blue rocks to the cave where the Historians lived. It was heaven to get out of the cramped base to where the blue caves yawned.
       The Historians moved gracefully inside their caves of indigo stone, their membranes surrounding and propelling them. Like the zoo, but better, because animals ignored you, whereas if you called, the Historian on duty would drift down to you. Huge but airy, filaments like robes trailing then billowing, the Historian would lower its great round face, with its strange duck-muzzle of whitish suede, and answer your questions.
       "Why is Dr. Timms sad?"
       Lys came every day to consult the record. Everyone at the base was permitted to do so, to check what had happened. Mum said it stopped people getting confused. Lys quizzed the Historians more than most. Her project -- making sense of the base and its rules -- was slow going, and required a lot of sideways thinking. The Historians often found it hard to connect the record, the things they'd been asked to hold in their regard, with the objects of Lys's curiosity.
       This time, the Historian told Lys a great list of things from Dr. Timms' recent record, mostly incomprehensible data from her experiments, before they hit on a likely solution. "Dr. Timms' work for the last month has been frustrating, terrible," the Historians concluded. "Dr. Timms is homesick."
       Lys tried a riskier question. "Why is Dr. Strickland angry?"
       "Dr. Strickland is not angry."
       "Oh. So what might make Dr. Strickland angry?"
       Lys knew asking this question was naughty. Rather than just trying to understand the scientists, Lys was also mapping the intrusions and the echoes, and trying to find reasons for them. Why did an intrusion of stocky, clumsy Dr. Strickland stomp from the East corridor into the mess, shouting Genevieve? Why did a mirage of Dr. Timms cry over her meal, long hair falling into her food paste? Lys had seen each of these intrusions three or four times. While the other base staff turned away, Lys hid under the mess tables and observed, like a good scientist. She could already tell whether something was real (even when they fooled Mum and Dad), but she also wanted to know which ones would come true and which would fade (which nobody could tell).
       But the Historian wouldn't reveal anything from the future. It was an agreement they'd made with the scientists, way back before the base was built. Now the Historian bobbed silently, refusing to reply.
       "Alright. Sorry. Why is Professor Bromford always scowling?" That wasn't about an intrusion; Professor Bromford scowled all the time. He owned the whole base but didn't seem happy about it, from the slice of visible face between his shrub-like hair and beard.
       This enquiry covered multiple periods of time, so the Historians had to tell Lys a great deal of the Professor's record and mentions of the Professor in other people's records (mostly complaints about pay).
       "Never mind," said Lys. "Thank you." The Historians never said please or thank you, but Lys found it easier to keep her Gran's manners in both locations.
       She watched the Historians in silence, noticing the sky-blue streaks on one, the violet dots on another. This was another observation project. Lys had realised that none of the scientists could tell the Historians apart and had vowed to learn how.
       Lys spent that whole holiday gathering information. The knot in her chest, from always being wrong, loosened a little.
       On the last day of her visit, she ran to the cave and summoned a specific Historian, the one surrounded by a flurry of metallic green-blue. "I know which one you are!"
       The Historian tilted its head. Intrigued, or offended? As Lys watched, its skirts darkened, then flared with a hundred pinpricks of violet. The Historian became a teasing neon firework show in the dim cave space. They had no permanent markings.
       Lys should have felt wrong-footed, but the Historians would never scold her, so she laughed and laughed as the creature bobbed and altered.

       Lys aged nine still strove to become an expert, but the more data she collected, the more the patterns broke down.
       "Your mummy was expecting you for months before anyone knew! Did she tell you?"
       Dr. Timms, the sad-faced scientist, announced this to Lys over dinner in the mess, while Lys peeled the sticky film off her meal tray.
       Lys knew Dr. Timms was trying to cause trouble. The previous week, Dr. Timms had stroked Lys's arm and asked: "You're a clever girl, aren't you? Do you know how to tell if an intrusion is actually going to happen?"
       Well might Dr. Timms ask, because she was Genevieve, and the intrusion of Dr. Strickland still roamed the East corridor bellowing for her at least once a month. The question had embarrassed Lys into silence -- an adult showing her ignorance, while still patronising Lys.
       Thankfully, this time, Mum was here. Mum reached sideways and gathered Lys in for a hug. "It's true, we didn't know for ages that you were on the way," her Mum said. "But when we found out, we were so happy!"
       Lys let the hug happen. She knew the fundamentals of how babies grew, but not how long they lurked unannounced. Was Dr. Timms just talking about the way that time ran differently on the base? Lys could feel the difference (along with the change of gravity). The Historians fixed it at a slower pace so the scientists could get more work done -- more weeks passed here, every summer holiday than at Gran's. Would Mum, therefore, have been pregnant for longer, or for less time?
       Lys needed more information, without upsetting Mum, so she slipped away to the caves.
       "Did Mum really not know she was pregnant with me, for ages?"
       The Historians set no limits on what she could be told. Once she'd asked why Dr. Strickland had smashed the mirror in his room, and received the response: "Dr. Strickland believes Dr. Timms has been cheating." Lys knew that wasn't about the scientists' weekly card game.
       This time, the Historians were working, sweeping their gaze to and fro, scooping up motes of gleaming dust. The duty Historian talked while they scooped. "Your mother did not realise she was pregnant, so did not add it to her record. We failed to hold it in our attention."
       That made sense. The Historians kept the whole base at a steady pace, but there were weak spots. The pregnancy could have quietly stalled.
       "How did Mum ever find out, then?"
       "Intrusions."
       Had Mum seen intrusions of Lys? Sometimes Lys caught a smaller version of herself skipping along a base corridor. A couple of times, Lys had even seen someone much taller, like an older sister. She had watched in awe and felt the gap of time between them like a cold wind.
       Or had her Mum heard Lys as a baby, crying in the night? Or could you have intrusions relating to your own body? A big belly suddenly shoving the dinner table.
       "After she knew, she recorded each day," the Historian added. Lys couldn't tell if they were trying to reassure her. Their manner was always so mild, so solicitous, but it didn't translate, you couldn't assume.
       "How? Like: Now I'm three months and one day pregnant?"
       "Yes."
       Lys imagined every complexity that turned a big-eyed bean into a baby. Ears. Fingers. "Did she have to know how I was growing?"
       "No. We held you in our attention, and made sure that you progressed."
       So the Historians had watched over Lys as she grew. Not let her slip backwards into nothing.
       "But nobody else had ever had a baby, here."
       "No."
       The Historian continued sorting points of light, pulling them into a grid in the velvety air by a series of hypnotic swoops. Then in a blink, they released the grid. The points flew apart in a sparkling blizzard.
       They're not working, Lys thought. They're trying to cheer me up like a clown making balloon animals.
       Then, to her surprise, the Historian volunteered a statement without Lys asking a question. "Your parents came here to perform experiments that can only be done here."
       "I know."
       In this place, the Historians could hold things still that would otherwise be over in an instant, or even run them backwards and forwards again in time, like a film. That was why Professor Bromford had built the base here. The scientists worked with those atoms which were too crowded for their own good. Without the Historians' help, the atoms would only exist for seconds, before flopping apart like a handful of frogspawn.
       "I know their work's important," Lys said dutifully.
       "I mean, only, this. . ." The Historian kept speaking. Lys couldn't remember them ever being so talkative. "Their concerns being primarily scientific, they did not foresee you and therefore did not prepare for the possibility. They worked everything out as they moved forwards. Yes?"
       The Historian spoke slowly. They weren't reassuring Lys. To them, Mum and Dad's headfirst stumbling through time was bewildering. They wanted Lys to help them to understand.
       That reversal of role felt worse than sea legs.
       As Dad tucked her up that night, she asked, "How did you know I'd be normal?"
       "We didn't worry about it." Dad's smile didn't include any hint of horror: a foetus that winked in and out of being, grew and shrank, a sperm escaping an egg and wriggling away. "And it's all worked out! Hasn't it?"
       Had it? Lys had heard muffled conversations through the metal walls of the base, with cadences of disappointment. And the tri-annual questions: are you top of your classes? You're not bottom, though? Where are you, compared to the others? Maybe Lys's furtive start explained their anxiety.
       She couldn't ask the Historians if she was normal. They'd never seen another child.
       "You're our wonderful girl." Dad hugged her and Lys, in his arms, turned restless and cynical. Dad wanted Lys to be clever and good, as evidence that he and Mum were more mature than the other scientists on the base, who paired up and broke up and (some recent intrusions suggested) would one day get into a wrestling fight in the mess.
       Lys wanted the hug, and Dad's reassuring lecture, to be over. She pictured herself pulling impatiently at his droning words.
       To her surprise, she found she was running Dad's voice faster, at least inside her own head. It became a quick, fluting twiddle.
       Then a long lull, and she realised he was waiting for her to speak. She loosened her grip on the pace around them, and let it merge again with base time.
       "Thanks, Dad."

       The following week, a new and persistent intrusion appeared: Dr. Timms kissing dishy newcomer Dr. Haus at the door to her room. Dr. Timms had to squeeze past herself to get out in the morning, or steel herself to push through herself.
       Lys privately considered it Dr. Timms' punishment for trying to start trouble with Mum.
       The kissing pair were horrible to look at -- you could see their tongues -- but the vivid intrusion helped Lys get better at distinguishing the tissue-thin separations between each moment, from deep past to far future.

       The incident happened shortly after Lys had made her record, one night. That meant she had a whole day to decide how to include it in her next record.
       Lys's record, aged eleven, was a dull list. Her parents no longer helped her make it. Sometimes she rattled it off in one sentence: Breakfast was porridge, walked three times round the top deck, watered the plants, read a book. She'd stopped including her feelings and fears (Rumi hasn't written back in a week; when I get back to Gran's she'll have made friends with someone else.). She didn't confess or assign blame. She stuck to the facts.
       She always started her record with breakfast. So where could she fit in the thing which had happened before breakfast, during the night? It was more properly part of yesterday's record, but that had already been made. . .
       All that day, she pushed away the incident. She went for a long walk with her parents, focussed on the blue terrain, and her Mum grew annoyed when all Lys's replies were mumbled. Lys longed to put the whole day on fast-forward, but she'd stopped experimenting with that, terrified that she might send parts of her brain out of sync.
       As an excuse to wander further away from her parents, Lys started hunting rocks, ones with soft, weathered domes like her paperweight.
       "Aren't you a bit old for that?" called Mum. "I'm not going to help you carry them."
       Lys hadn't asked her to. Lys didn't follow her parents back inside, but stood at the base door, cradling her heavy armful. She palmed a rock and swung it, flung it outward. It sailed a satisfying distance, because of the lower gravity.
       Lys held the next rock in her hands and her attention, and wrapped it in slow time. Why not? It was a stubborn lump, impossible to harm. The wrapping was an imprecise bundle, like crumpled tissue paper round a teacup.
       She threw it. It shot off towards the horizon, then slowed; Lys perceived its wrapper of time burning away as it flew, like the icy aura around a comet. Just at the point where it was nearly out of sight, it dropped limply to the ground.
       When Lys reached bedtime, the question of her record grew unavoidable.
       She could skip a record. But she hated the muzzy feeling that followed, whenever she tried to recall that day. She'd skipped records for a week, once, but then events had echoed (breakfast butting in on breakfast) or vanished entirely. Lys had even tried holding things in place herself, but it took the Historian's unflagging attention to fix an event entirely.
       Where in the day's record should she fit the incident?
       And the more horrible thought, which had been lurking underneath that question: how could you even say it?
       She silently formed a phrase. Professor Bromford was in my room.
       She hopped over the part she couldn't speak. After Professor Bromford left, I pushed my cabinet against the door. Her bedroom door at the base didn't lock. The cabinet wouldn't keep someone out, but the noise of the door rattling against it would have woken her up.
       If she recorded those two things, there would be a gap in the middle of the record. What would that feel like tomorrow? Itchy? Like a glitch, or a missing tooth? Better or worse than filling it?
       Lys told the record about her breakfast and her homework and the long evening walk to gather stones, and nothing else.

       The following day, Lys buried herself in homework. Concepts from teachers had begun to catch up with things she'd heard from her parents. When the teacher had described the largest elements -- big bubbly clusters of protons and neutrons that fell apart as soon as they got together -- Lys had recognised them as old friends.
       The homework wasn't as calming as Lys had hoped, because Lys remembered that she'd told the teacher that her parents worked with transuranic elements.
       "I don't think so," the teacher had replied. "They only exist for a tiny, tiny time." He'd turned away so as not to embarrass Lys, like the base staff ignoring an intrusion.
       Lys's cheeks burned again in recollection. Seeking to be soothed, she took her homework to her mother. "Look what I'm studying."
       "Oh, wonderful! Well done. Just like your father and me."
       "Could I see some? Real ones?"
       Lys kept a wary eye out for the Professor as they walked together to Mum's lab. But Lys only saw a few scientists, including those truly present (playing poker, reading, idly arguing) and those who were intruding (weeping, slapping a doorframe in anger).
       At Mum's bench, they peered together at charts with sudden spikes, at graphs with anomalous blips. Mum showed the experiments where the Historians had slowed the atoms down, prevented their decay, or even reversed it.
       "Where are they, though?" asked Lys. "The atoms?"
       "In here."
       Lys's Mum pointed to a row of featureless steel boxes. Lys's heart sank. Lys realised she couldn't see a transuranic atom the way she had imagined them, like clusters of balloons, swelling up and jostling, then bubbling over, neutrons and protons popping outwards. And then the reverse of the process, with errant components sheepishly shuffling backwards and huddling together again, as the Historians wound back time and drew them in. Lys would never see the mystery which gave purpose to the base.
       Then shouting started in the mess.
       "You stay here," said Mum, but Lys didn't.
       Dr. Strickland lurched around the mess, bellowing at Dr. Haus. Dr. Haus (nimble in the low gravity) dodged away from him, but Dr. Strickland soon cornered him against the work surfaces.
       Dr. Haus punched Dr. Strickland in the face. That was quite horrible.
       The next part was familiar: some clumsy grappling that Lys remembered from an intrusion. It had finally come true. Mum and the other scientists stood around the edge of the room, feebly urging both doctors to stop.
       Lys ducked under a table, as she'd done when small, to stay out of the fight but keep watching. Dr. Strickland roared and made a doomed attempt to pick up Dr. Haus, and they both stumbled into a part of the mess that Lys couldn't see.
       A figure was crouched further under the table. A younger Lys, rounder in the face and with her knees pulled up to her chest, hiding and watching the intrusion, years previously. Maybe there was always an echo of Lys down here, while the base went about its business.
       Lys concentrated and reached over. The gap between them was cobwebby and cold, and Lys only managed to pat the younger girl briefly on the shoulder. The child looked horrified.
       The base was too full, Lys thought, as the two of them waited for the men to stop fighting. Maybe there was enough space for the scientists, but not enough space for their anger and pride, or the intrusions of what they might do, or the echoes of what they'd done. Even the Historians couldn't hold the base together.

       Lys continued to avoid the Professor. It was easy enough, particularly after the fight; half the base's scientists were avoiding one another, and nobody compelled Lys to be sociable.
       The first time she saw him in the mess, he looked away, and Lys had thought: Oh, so that's how it will be. We won't speak of it. Which was a relief. It let the night's incident slip further away into half-happened.
       She even avoided the Historians for a few days. She felt unexpectedly hot-faced at the whole idea of these gentle, strange (be honest) beasts looking over years and years of her childhood. She remembered her Gran asking Dad: "You're letting those things babysit your daughter?"
       But then she missed their tranquillity, so she went to their cave, where they were tracing connecting lines of light in every direction in the air.
       "What happens when people break the law, here?"
       The Historian's skirts fluoresced as they descended. "Which law?"
       Lys, unable to tell, had to think of a different example. "Like the fight, last week."
       The Historian's response took time. A lot of the scientists had rushed to see the fight, so there'd been many contributions to the record. Lots of juicy detail.
       "Dr. Haus has apologised."
       That made Lys feel sick. If Professor Bromford apologised to Lys, it would be an acknowledgement of what had happened. People would know. Then her parents might insist that she had to accept his apology. It was intolerable, dragging Lys into complicity.
       "How do they deal with proper crimes?"
       "They did not prepare for the possibility."
       "Do they make it up as they go along?"
       The Historian didn't hear the sarcasm. It tilted its huge, smooth muzzle and continued. "Some suggested that the act of recording would discourage lawlessness."
       "Ha!" The Historian fluttered away from her ridicule. "Sorry! Sorry." Lys tried to speak soothingly, to bring the Historian closer again -- silly to be able to startle them, when they were the size of elephants. Lys tried to remember the trip to the zoo when she was five, where the animals had reminded her of Historians, and vice versa, but her memories of animals were gone. There was only the memory of crying at bedtime.
       "Can you tell me what'll happen if I do something?"
       The Historian oscillated regretfully. Lys knew the rules but had hoped the Historians might bend them. Were they fond of her? No, or not enough.
       She had decided, anyway. Laws didn't apply, here. And what Lys really wanted was for the Professor to be sent away. That wouldn't happen, because the research base belonged to him.
       Similarly, she knew her parents wouldn't leave. The base let them do unique things. If she told them what had happened, she'd have to suffer their distress, and their efforts to comfort her, and then explanations of why they'd decided to stay. She'd probably end up having to comfort them.
       How easy it had been for the Professor to drive a great wordless wedge between herself and her parents. But 'wordless' went both ways. She refused to give the incident any more clarity or continuity. She wouldn't tell the record, or anyone else.

       Two weeks later, at midnight, it happened again. A figure passed between Lys and the door, then a dry, hot hand on her leg. Lys, still paralysed by sleep, forced the air from her lungs in a moo of protest. She struggled and kicked -- connected with nothing, the intruder only an intrusion.
       No, an echo -- rarer than an intrusion, but just as sharp. A thing that had happened, but unrecorded, untethered from time, might happen again.
       A metallic banging jolted her fully into the present. Someone had opened the door to her room and hit the obstructing cabinet. "Lys, what is it?" Only her Dad, trying to get in.
       "Nothing. Nightmare."
       The third night it happened, Lys heard her parents talking in their cabin: . . .distracted. Falling behind, do you think?
       The next day Mum made a soft suggestion that Lys might want to cut short her visit and go back to Gran.
       She dashed out of the base, down into the caves, to say goodbye to the Historians.
       "Echoes only happen here, don't they? They'll stop when I'm back with Gran."
       The Historian flicked its muzzle, indicating uncertainty. "I do not know about your home."
       Lys imagined the Historians as jellyfish, beached on the shingle under the white sun. That made her too sad. She pictured them instead in her Gran's church, the place most like their caves, floating in the high space over the altar.

       The routine at Gran's, and at school, reassured Lys. The echoes ended. Gran asked why Lys had come back early. Trying to choose between lies, Lys couldn't reply.
       Gran took her to the beach. Instead of blue air, white water lapped and surged around Lys's skin. Lys swam hard, came ashore, and fell asleep on the shingle.
       She woke in terror and kicked out. Gran was reeling back, hand still raised from patting Lys's thigh to wake her.
       "Don't touch me like that," Lys said.
       Gran frowned. "Why not?"

       On her return to the base, the following holiday, nothing would stay in place.
       Some days, the incident wasn't in her memory at all. It should have been a relief. But her memory of the memory remained: the fear, the circular obsessive reasoning, clustered round a nugget of nothing.
       Some nights it happened again. She never became quite fast enough at telling the phantoms from reality, at shaking them away. (It never truly happened again. Lys played the sulky teenager to avoid the Professor.)
       After a week, Lys went to the caves. A Historian wallowed towards her through thick navy air. "Welcome, Lys."
       "Can I put something on record for the past? Which I didn't record when it happened?"
       "Yes." For them, it would be as simple as slotting an envelope into a pigeonhole.
       "Some time in April."
       She could feel their efforts as they picked through the gauze of the past. They told back to her the record she had made that month, a litany of breakfasts, until she recognised a particularly stilted day. "There. Add it there. Please put in my record the Professor came into my room in the night and put his hand on my leg. When he left, I moved my cabinet in front of the door."
       She felt them fix the incident, push a pin into it.
       It had a gap at its heart, but an outline of the incident had passed into the record now. It was public, which made Lys nauseous, but nobody would find out unless they asked the right questions.
       The echoes ended. Images twitched into her head from time to time, but they could be pushed out again.
       Professor Bromford was a creepy old man, Lys told herself. The kind of person her Gran warned her about. It felt good to categorise him. Lys continued to sleep with her cabinet against the door, and her stone paperweight in her hand.

       After weeks of successful dodging, Lys turned into the mess one day and saw him there.
       The Professor's hair was combed lower than usual, in a ridiculous attempt to disguise the red lump of his nose. A crack crossed it, made of caked blood where the skin had split.
       Lys ducked back into the corridor she'd come from. Then down, out, into the caves of the Historians.
       "Why has the Professor got a broken nose?"
       The Historian fluttered while consulting. "There is nothing in the record." Regretful that they were unable to help but otherwise serenely uninvolved. If they'd shown an interest, Lys thought, the base wouldn't hand over their thoughts half so willingly.
       Lys watched the Professor.
       The following day, his nose didn't have a mark on it: pale and big as ever. The next day, it had mostly healed. The following day, it looked like a terrible just-smashed mess. Instead of healing over time, it pulsed in and out of its ruined state.
       Lys knew what that meant. An echo had entered his flesh. He hadn't put the accident that caused it, or the fight, into the record. Overlooked by the Historians, the injury was only intermittently remembered by his body.
       Had someone hit him? Nobody's record mentioned injuring Professor Bromford. Lys imagined he might have struck himself in the face with a piece of kit, and felt too embarrassed to record it. Coward. If she could record the incident, then he could record a stupid accident.
       Had the Professor hoped it might resolve itself into never having happened? But his face these days was almost always damaged.
       He must be experiencing echoes of the fight, or the accident, almost daily.

       The base had passed a long way into decay. It was hard to sit down in the mess because there were multiple intrusions of Dr. Timms at the mess table, now, two or three of them at a time, crying for different reasons. Several Stricklands took turns to yell at her.
       Lys grew so used to ignoring them that one day she found herself eating lunch while the real Timms and Strickland had an in-the-moment row. They, in turn, ignored her as easily as they would an intrusion and kept arguing.
       "I didn't do it the first time!" The authentic Timms rasped, between hiccups. "You said I'd bloody well done it. But I didn't! But he kept coming back!"
       "So you thought: Why not?" shouted Strickland. "Why shouldn't I help myself to a bit of that? Was that it?"
       "God, no! I thought I must have to do it, on some level. Or why would it keep happening? Every time I got up, every time I went to bed, he was there. . ."
       "So you did it!"
       "So I bloody did it!"
       When they ran out of breath, the voices of other Timms and Stricklands picked up the refrain in the nearby corridors, row without end. Why didn't they leave the base? Lys wondered. Why stick around, when you knew more of the same would be coming?
       At the same moment, Lys realised she had never seen an intrusion of herself which was older than herself, right now.
       Lys went looking for her parents.
       "I feel really strange a lot of the time," she explained. "When I'm here at the base. Sort of sleepy, and just -- more stupid. Is that possible?" Lys knew what buttons to press, what questions they asked one another at night. She deliberately conjured up that horror, of herself as a foetal interloper, an indefinite tadpole for -- how long? Months? Years? And then switching between two ambient time-speeds, her young brain malleable, warping. . .
       Mum's face was ashy. Lys felt bad and included a less terrifying explanation: "I wondered if it was the low gravity."
       "Darling, we should get a doctor to look at you."
       "Yes, but I thought I could leave early. And see if I feel better. And maybe stay with Gran next holiday."
       "Yes! God, yes." Dad nodded and nodded. "We'll come and see you instead, stay with your Gran."
       Lys drank in the sight of them radiating concern. They hadn't planned things well at all, but they had good intentions.
       And now Lys was free to leave, which only left a few days to do the thing that needed to be done.
       Lys went down to the cave of the Historians.
       "I won't come to the base again, for a while. Maybe never."
       "We will miss your visits and your contributions to the record." They said it as a courtesy, a nod to her own experience of their separation. For them, she would always be there, like everyone else who had ever visited the base. They probably knew whether she'd ever come back, but had promised not to answer that kind of question.
       They'd probably refuse her next request, as well. She tightened her fists.
       "Will you do something for me? I don't know if it's possible. There's one night, one thing that happened. It used to come back, to echo, before I put it in the record. Can you unfix it? Can you encourage it to happen again?"
       The lights along the Historian's robes rippled like breathing. "The base staff have agreed to be bound by linear time."
       "I'm not a scientist. I didn't agree. I'm not trying to change anything, not really." She told them what she meant to do, and why she suspected it had already happened.
       They floated, silent and lambent.
       "Come on. You can help me, and I can do it then, or I'll just do it now." Her heart hammered as she bluffed. She hadn't the nerve to do it now.
       "We can show you your record." They rifled back through the record, spreading it out as Lys had never before experienced. It felt similar to when they'd added the incident to the record, months ago, but now Lys was more alert to it. She felt the full texture of the record, the dots of light among the layers, the fluctuation of tension around the things being held in place, the varying tissue thicknesses of all her days.
       The Historians fanned out the hours of that one night. They held out to her the moment of the incident. "We cannot give you any assistance in changing it."
       Lys stared dumbly at them, on the edge of tears. Why taunt her like this?
       Then she understood. She reached out and unfixed it herself.

       At the door of the base, Lys remembered how she'd stood here, the day after the incident: resenting her parents, hiding from the Professor, hurling her anger towards the horizon.
       Now she reached back through the filmy, slippery moments. She felt the anomaly where she'd thrown the time-wrapped rock.
       She pictured a proton coming back to its atom. She tried to draw the rock back to her hand. She pulled with all her effort, making herself sweat and shake. The sky stayed blank, and the rock remained lying out there, nearly at the horizon.
       Lys let it go. It was enough to stroke her attention back and forth along the arcing scar of the rock's trajectory. It was enough to have a plan, even if it wouldn't undo what had been done.

       The echo came in the second half of the night. Lys hadn't slept. She heard footsteps in the corridor, moving away.
       Lys swung her legs round, dropped to the floor. From the bedside table, she scooped up her indigo rock paperweight, the dome fitting neatly into her palm, and followed the echo of the Professor.
       She didn't try to be quiet. She walked three steps, each one like tearing through cobwebs. She reached for his shoulder with her hand and her attention, and grabbed.
       He was wrenched round to face her, and it needed hardly any strength to swing the rock. It crunched into the bridge of his nose, and his head snapped backwards.
       The Professor fell to the floor, snorting, labouring to breathe. Then he was gone, the moment of the incident slipping away like a shadow.

       It wasn't yet morning when Lys ran down to the caves.
       "I hit Professor Bromford in the face with a rock. I want to add it to my record."
       A public fact, now. Semi-public, because the Professor's nose had been broken for weeks -- anyone who was interested had probably already asked the Historian What happened to the Professor's face, for Christ's sake?
       Lys didn't care, either way. She didn't fear people asking the Historians, and she didn't need it.
       What she wanted was for someone to ask the Professor: How did you break your nose? Because then he would be forced to lie, as he'd forced her to lie. To pick around his memories for some acceptable substitute, as she had to pick when her parents asked: What's wrong? (What's wrong with you?)
       Maybe the Professor would only be asked rarely if he stayed out here on the base, only when a new scientist joined the team. But it would happen, on and off, for the rest of his life.
       "Is this how things normally proceed?" asked the Historian, with unaccustomed curiosity. Lys remembered a Historian using the same tone when they had discussed her gestation. They worked everything out as they moved forwards. . .? And she'd been ashamed of how humans fumbled along when these creatures were so graceful.
       "I don't know how things usually work. I don't know if things work at all."
       Lys thought of the chaos of the base, the nervous silence of her family. She remembered the conflicting rules she had tried to learn, and how they hadn't protected her.
       She wouldn't learn rules anymore, she decided, and her step was light as she walked away from the cave. She would make up her own rules, and work everything out, and keep moving forwards.