'There are cameras you know about,' Speller Twain said, 'and there are cameras you don't know about, the ones their so-called peace officers planted. That little flash will have taken care of anything, sound and vision.'

He sat on a drum of powdered growth medium, told Macy to sit on another, and said, 'You know why I'm here.'

'I did what you and Mr Ifrahim asked. I met her. I told her-'

'Let's get you wired up first,' Speller Twain said, and pulled a stiff black handkerchief from his bag and asked Macy if she knew what it was.

It was a magnetic resonance imaging cap. Macy had worn one once before, back when she'd been a labourer, at an inquiry into the deaths of five of her workmates after bandits had tried to overrun their site. It measured activity in Broca's area and Wernicke's area, the regions in the left hemisphere of the brain that controlled linguistic ability. There was heightened activity in the two regions when you answered a question, synchronised if you told the truth, showing millisecond differences if you lied or dissembled.

'There's no need for this,' Macy said. 'I want to tell you what happened.'

'Let's hope you do. Hold still.'

The cap adjusted to the contours of Macy's skull, applying an unpleasant grip across her forehead and ears to the nape of her neck. Speller Twain took out a slate, shook it into stiffness with a practised flick of the wrist, and studied the images transmitted by the cap while showing Macy a series of simple geometric patterns on flash cards and asking her anodyne questions to establish baseline brain activity.

'We're good to go,' he said at last. 'Tell your story, and don't leave anything out. I'll know if you do.'

Macy gave a brief account of her meeting with Ursula Freye, and the security chief questioned her closely, digging up all kinds of things she didn't know she remembered. He was especially interested in Ursula Freye's companions.

'They wore these big fur coats like everyone else in the bar, and they were masked,' Macy said. Sitting knee to knee with this big man who seemed to take up most of the cramped space, cramming her into a corner, she felt a crushing claustrophobia. His square, solemn face unreadable. His gaze dark and cold and unblinking. 'I didn't see their faces and I didn't see their hands, either, so I can't tell you what their skin colour was, or make a guess at how old they were. I don't even know what sex they were.'

'But you said that they were Outers.'

'I guess they were. The one who stayed behind was pretty tall. Taller than you, I think. The two who left weren't much bigger than me, but that doesn't mean they weren't Outers. They could have been first-generation, or even pioneers. I mean, there are still plenty of pioneers alive, aren't there?'

' "I guess" isn't good enough. I need hard facts,' Speller Twain said, and stuck two fingers in the breast pocket of his coveralls and lifted out a bright red drug patch and peeled off the backing with a fingernail.

Macy said, 'Now wait just a minute, you can't-'

'Yes I can.'

Speller Twain caught her when she tried to stand, pushed her down with one hand and slapped the patch onto her temple with the other, effortlessly fending off her attempts to pluck it off as a slack numbness spread through her body.

'All right,' he said, after a little while. 'Why don't you tell me the name of the first person who fucked you?'

Macy didn't want to answer, but the words bubbled up like marsh gas and she couldn't help blurting them out. 'Jax. Jax Spano. And fuck you for doing this.'

'Fuck you right back,' Speller Twain said evenly, studying his slate.

'You Fontaines, you think your shit doesn't stink like everyone else's. Let me tell you that it does. We'll go through it again. From the beginning.'

They went through it again, from the moment Macy had stepped onto the escalator and descended into the free zone, to the ride on the tram back to the park's dome. Speller Twain and the room seemed to recede to a great distance and she heard herself talking about things she had no memory of seeing or hearing. It seemed that the two people who'd left when she'd met with Ursula Freye had moved in the gliding way characteristic of people born and raised in Callisto's low gravity, and had been wearing Outer-style slippers. One pair patched together with differently coloured felts, the other woven from strips of plastic. Maybe these were false memories, or nothing more than a drug fantasy, Macy didn't really care, and at Speller Twain's prompting babbled on, giving word-for-word accounts of the conversation with Ursula and her fox-faced companion.

At last, the big man leaned back and said, 'Just one more thing I need to know. Why did you follow her to that bar? Why go to all that trouble when you could talk to her right here?'

'I wanted to catch her out. And I thought she would talk more freely if there weren't any cameras around.'

'What else?'

'I didn't want you to spy on me.'

'Didn't work, did it?' Speller Twain said. 'Don't worry. I'm not mad at you. You gave me what I needed to know. What you can do now is sit tight. I need to figure out the next move, so don't do anything else until you hear from me.'

He stripped the cap from Macy's head and rolled up his slate, then speared another patch from his breast pocket, a white one this time, and with surprising delicacy stuck it on Macy's left temple.

'The antidote,' he said, and stood up, slung the bag over his shoulder, and opened the door of the little storeroom.

'Wait,' Macy said. 'Ursula wants me to make her a copy of the work logs. What should I do?'

'I already told you,' Speller Twain said. 'I don't want you to do anything unless I tell you to. And don't talk to anyone about this. I don't need to tell you what will happen if you do, do I?'

Then he was gone. When Macy stood up, a ripe wave of nausea flushed through her. She made the bathroom just in time. Afterwards, she stripped off her sweat-soaked coveralls and underwear, showered, put on fresh clothes and pulled the tab from a fresh cup of coffee. It took a while to drink it: she couldn't stop her hands from trembling.

Macy was working on another cup of coffee, her third, when her assistants came in. She told them that she'd gotten drunk with Ursula Freye in a bar in the free zone and had sorted out some family business, she was grateful for their help but everything was fine now, they needed to get down to some serious work. Argyll and Loris seemed to accept these lies with equanimity and Macy found that she was envious of their innocence, the simplicity of their lives in a city where everything was out in the open and nothing was hidden. Where people were more or less equal, where there were no bosses, no secret policemen who trapped you in a closet and mind-raped you. Where sin was an option on a menu displayed in a theme-park red-light district, and never followed you home.

She explained her thoughts about the Skeletonema problem, and they had a conference with the leader of the plankton team, Cristine Quarrick, who agreed to run a complete DNA and proteome profile of the diatom, paying special attention to half a hundred key enzymes and the genes that coded for them. Meanwhile, Macy and her assistants would try to find some time to run some simple experiments to check the diatom's phosphate uptake system and investigate nutrient binding in the melt water, but first there were the usual housekeeping tasks to be done.

Late that afternoon, they were working amongst the giant tubes and open vats of the bioreactors, taking samples to measure the viability and composition of the various cultures, when Loc Ifrahim called Macy. She ankled away from Loris and Argyll and put on her spex, and the young diplomat smiled at her from a virtual window that seemed to hang a metre from her face.

'I won't take up much of your time. I know that you are very busy.'

'I'm also all out of favours.'

'I'm not asking for a favour, Macy. I am asking for cooperation.'

'And if I don't show willing, Speller Twain will pay me another visit. I know the drill, Mr Ifrahim. Why don't you just tell me what you want me to do?'

Loc Ifrahim's smile was a work of art, solicitous, sympathetic, and about a millimetre deep. 'You have much to do before the opening ceremony, and you're worried that this will take up valuable time. But don't worry. What we'd like you to do is very simple, and won't interfere with your work in any way. You told Mr Twain that Ursula Freye wants to examine the work logs. She cannot access the database because Mr Twain has suspended her privileges for the duration. Quite legitimately, of course, because she could be tempted to hack into it and alter the data to suit her fantasy. So she asked you to make a copy for her. That's all I want you to do.'

'You're giving me permission to do this.'

'I can hardly do that; I have no authority over anyone in the construction crew. No, all I can do is ask you to do this out of goodwill, for the best interests of the project. After you give Miz Freye the logs, you see, she will analyse them and find nothing in them to confirm her fantasies of conspiracy and sabotage. And that, hopefully, will bring this unfortunate matter to a close.'

'What if she's right? What if she does find something?'

'You are worried about blowback. There's no need. Three biome economists back on Earth have checked this data set independently, and none of them found anything untoward. All you have to do, Macy, is give her the logs and walk away.'

'Give her the logs and walk away. That's it?'

'That's it.'

'Does Mr Twain know about this?'

'We have discussed it extensively. He agrees with me that this is the best course of action. In fact, he believes that it is essential. He was most insistent on that point. And I know that he is an impatient man who doesn't like to be kept waiting. So, Macy, I think that you had better do it sooner rather than later, yes? And don't forget to tell him when it's done,' Loc Ifrahim said, and cut the connection.

Macy walked out along the jetty, thinking things through. The first lesson she'd learned after signing up to the R&R Corps was that keeping a low profile was an essential survival strategy. Obey orders, don't ask questions, never make a smart remark. Do your work, mind your own business, and most of all, never, ever get involved in disputes between your superiors, because if you do you'll most likely end up as collateral damage. Well, she thought, she'd been shoved straight over that line now. She was in bandit country, walking a narrow path towards an unclear destination with all kinds of unknown dangers lurking in the bushes on either side and no possibility of retreat. If she refused to do this little favour, Speller Twain would come after her, and at best she'd be looking at charges of insubordination, wrecking, and anything else he could throw at her. But if she went through with it, she couldn't be sure where it would lead; Loc Ifrahim's assurance that she wouldn't have to do anything else after she gave Ursula a copy of the work logs was about as much use as a bucket of warm spit . . .

She wished that she could talk about this with someone. She wished that she could let Argyll and Loris know what was going down, maybe ask for their help again, but she couldn't risk letting them know that there was something rotten at the heart of the crew. They were bound to ask all kinds of impossible questions, and if word got back to Loc Ifrahim or Speller Twain she'd be in even more trouble.

Well, maybe she didn't have any choice about giving Ursula a copy of the work logs, Macy thought, but she was damned if she was going to skulk around any more. So while Argyll and Loris finished their work on the cultures in the bioreactors, she downloaded a full copy of the work logs to a data needle and set off for the main island, where most of the crew were based.

The gentle contours of the island had already been landscaped, with broad green lawns spread either side of a central ridge planted with a nascent forest of stone pine, Monterey cypress, maiten, and boldo. Big chunks of dark green and black pyroxene rock, veined with crystals of shock-activated glass, stood amongst the young trees along the top of the ridge like scales on a dragon's back. All the plants had been force-grown in farm tubes from seeds and seedlings imported from Earth, tweaked to grow in the biome's relatively low light levels, and transplanted according to the designs of Artemis Lampathakis and Aurelio Ochoa, who had based the ecoarchitecture of the biome on the dry and temperate climate of Cordillera de la Costa on the Pacific coast of Greater Brazil. Evergreen trees and flowering scrub along the shores of the lake; a desert apron beyond the southern end, yet to be planted out with cacti and agaves and clumps of Washington palms.

The crew's living quarters and main worksuite were housed in a flat-roofed building at the northern end of the island, near the entrance to the railway that linked the biome with the city. The worksuite was open-plan, with islands of couches and chairs and memo spaces, a long table where the crew gathered every few days to talk about progress and snags. Tall picture-windows along one side looked out across a channel, almost completely flooded now, to a promenade along the western shore and apartment buildings tucked under the hem of the tent. Macy stalked down the length of the worksuite until she saw Ursula Freye, curled catlike in a sling chair with a slate in her lap and papers spread out on the halflife grass floor around her. Ursula looking up as Macy came over, starting to say something.

'Here's what you asked me to get,' Macy said loudly, and threw the data needle at Ursula.

It struck Ursula above her small breasts and fell onto the lighted screen of her slate. Ursula picked it up and called after Macy, who was already striding away, feeling her face heat up as everyone in the worksuite turned to look at her.

But at least it was done, and she'd done it right out in the open in front of plenty of witnesses - no skulking around, no secrets, nothing to conceal.

7.

Macy immersed herself in her work, staying in her lab as much as possible so that she wouldn't run into either Ursula Freye or Speller Twain, and tried to forget about what had happened. Tried to forget that Speller Twain could come back at any time and do whatever he wanted to her. Ursula Freye was protected by her consanguinity, but the security chief had demonstrated that Macy was just a grunt whose life and career were at the mercy of the whims of her superiors.

One piece of good news: Cristine Quarrick discovered that the Skeletonema cells weren't producing enough copies of the transport protein that bound phosphate ions externally and then pumped them across the cell membrane, which seriously reduced the diatom's ability to take up the nutrient at ambient levels in the melt water and was almost certainly the explanation for the low growth rates. Cristine used a transcriber to manufacture loops of DNA containing the genes that coded for transport protein production and added them to a small sample of Skeletonema cells via an off-the-shelf retrovirus, and this treatment ramped up doubling time and photosynthetic efficiency close to optimal levels. Producing enough retrovirus to infect the mass cultures of the diatom would cause a slight delay in production, but it wasn't serious. A matter of days, not weeks. They could easily get it done before the opening ceremony was scheduled to take place, and that was all that mattered.

When Macy asked Cristine if she had gotten around to doing a complete genomic analysis of the diatom, Cristine said, 'The genes for phosphate transport proteins are there, if that's what you mean. They just aren't expressing properly for some reason.'

'I was wondering if it was something that could be fixed more easily than adding extra copies of the genes.'

'The problem is fixed,' Cristine said, a sharp edge entering her voice. She was a brisk, brittle woman who didn't take kindly to any hint of criticism.

'And I have plenty of work to do without making more work.'

So Macy could put that problem to one side, and get on with growing up her own cultures of microorganisms. She discussed tweaks and snags in the quickening of the marsh ecosystem with Tito Puntarenas and Delmy March. She supervised the draining of a bioreactor where blood-warm temperature and the activity of more than three hundred species of bacteria and microalgae and protists had quickened a slurry of smectite clay fines and carbonaceous chondrite material into rich black living mud. Argyll and his father, a languid, nut-brown centenarian, one of the Outer System's best soil chemists, had helped Macy modify methods routinely used on Earth for the base materials available on Callisto, mostly minerals derived from palagonitised basalts mined from impact craters. Macy had learned a lot, and had been very impressed by the tour that Argyll's father, Jael Laudrisen Hall, had given her of the facility where topsoil was manufactured. It was far more difficult than making mud. Soil was not a random mixture of inorganic, organic and living material; it was highly structured at every level, fractally so. Stratified and textured and dynamic, it supported a myriad complex chemical reactions that were still not completely understood, methated by soil water and air moving through pore space's that occupied up to fifty per cent of soil by volume. Soil water also transported material through processes such as leaching, eluviation, illuviation and capillary action, and supported a rich and highly diverse biota - hundreds of varieties of soil bacteria of course, and cyanobacteria, microalgae, fungi, and protists, as well as nematodes and worms, and insects and other small arthropods that recycled macro-and micro-nutrients, decomposed organic material, and mixed and transported and aerated mineral and organic components. In natural conditions on Earth, it took about four hundred years to produce a centimetre of topsoil; a thousand years to produce enough to support agriculture. A significant proportion of the work of the Reclamation and Reconstruction Corps had been concerned with replacement of topsoil lost by erosion caused by overfarming, or poisoned by industry during the twentieth and twenty-first centuries, or stripped away by floods and hyperstorms during the Overturn. So Macy was fascinated by the huge reactors, vats, tanks, and table pedons where topsoil similar to the rich black chernozens of temperate grasslands of Earth was manufactured. AIs monitored and micromanaged every stage of the process, but really it was more like alchemy than chemistry, and a major expenditure of energy and effort.

'We don't need soil for the hydroponic farms, of course,' Jael Laudrisen Hall told Macy. 'And we could use humus and sand ground from basaltic glass as a substrate for the plantings in our parks and gardens, grow them like so many pot plants. But most plants grow better in soil, and it serves as a valuable buffer that helps to stabilise our enclosed ecosystems. And besides all that, it feels better between the toes.'

Making mud was somewhat easier than making soil, but as far as Macy was concerned it was an equally honourable profession. As important as anything the construction crew did and maybe more so, for mud was at the base of most flows of nutrients and organic material in the biome's enclosed aquatic ecosystem. And there was an immense satisfaction in using carefully calibrated cultures of microorganisms to transform material left over from the creation of the Solar System into living mud, a self-organising bioreactor that structured itself into microdomains within upper aerobic layers and lower anoxic layers and could consume just about every kind of organic material and reprocess inorganic nutrients and return it all to the cycle of life. To the amusement of her two assistants, Macy drew off a small measure as it was pumped out of the bioreactor, tasted the gritty gruel and pronounced it good, nice and lively. Just right for the hectares of reed beds that the gardening team were growing in one of the farm tunnels under the city, ready to be transplanted onto shallow banks along the eastern edge of the lake once it was filled to the brim.

Macy's work was important, and there was so much to do. Five days after she had delivered the copy of the work logs to Ursula Freye, she and her assistants went out to check the reef in the channel to the west of the little archipelago that was being built beyond the main island. It was a broad table several hundred metres long, dissected by a maze of ridges and channels designed to maximise mixing of water driven through them by wave machines at the southern end of the lake. When the lake reached its final level, the ridges would be just a metre below the surface, and Tito Puntarenas and Delmy March would seed them with sponges, soft corals, and species of red algae and kelp tweaked to grow in fresh water, providing a habitat for fish and crabs and shrimp. In the channels between the ridges, sandy sediments rich in microorganisms and stabilised by a matrix of blue-green algae and the mucus-lined burrows of several species of tube worm and shrimp would filter huge volumes of water and provide a major contribution to recycling suspended organic material and essential nutrients.

The lake had begun to flood the reef a couple of days ago. The water listlessly sucking to and fro at the bottom of most of the channels was a lifeless yellow-brown soup thick with fines, but Macy and her assistants had sealed off a couple of dozen of the channels and laid down various mixes of quickened sediment and filled them with filtered melt water. Now, before the rising level of the lake overtopped the little dams that stoppered the channels, they motored out to the reef in a skiff and took samples. On-the-spot DNA sampling suggested that most species of bacteria and microalgae in most of the mixes had flourished, and Macy was in a good mood as Loris steered the skiff past the flank of the coffer dam that encircled the construction site of the new archipelago, heading back to the lab.

The tops of islands rose like small hills above the dam's low black wall. One was crowned with a grove of cypresses and the white pillars of a shrine in the style of ancient Greece; others were turfed with flawless green grass or planted with clumps of palms: the last and largest island was still being constructed by a balletic flock of robots perched on a pile of elaborately cross-braced scaffolding that looked like a truncated version of the Eiffel Tower. Their triangular heads. equipped with hundreds of tiny spinnerets that extruded fullerene composite strands as strong as diamond, bobbed and gyred as they patiently lengthened the spars and struts of the island's skeleton. One stood with its swollen abdomen pointing into the air and its head bowed while a technician raked clogged spinnerets with a wand spraying needle jets of water.

Argyll, who'd been watching the robots too, said, 'It's going to look wonderful when it's finished.'

'As long as no one decides to put some other last-minute change to the vote,' Macy said.

'You have to shake off your linear thinking,' Argyll said. 'This isn't a top-down hierarchical society like Greater Brazil. This is the Outer System. We do things differently here.'

'I know,' Macy said. 'Everything is provisional, and everyone has the right to an opinion on anything, even if they don't know the first thing about it. I'm amazed you get anything done.'

'Well, we're not afraid of hard work,' Argyll said.

'Nor are we. But it makes things a lot easier if you know what you are going to do before you start to do it.'

'Easier doesn't mean better.'

'Easier, and less wasteful,' Macy said. 'I don't know why anyone ever thought democracy was a good idea.'

'The city has a surplus of robot labour,' Argyll said. 'And the islands really aren't much of an expense compared to the total cost of the biome. The only raw materials are graphite slurry to make the framework, a few boulders, and a couple of hundred tonnes of topsoil. And it really is going to look beautiful when it is finished. A shoal of little green islands with sailboats and waterskis threading through them, people picnicking on them . . .'

'One thing we can agree on,' Macy said. 'We've taken your crazy ideas and made something good from them.'

As they rounded the southern end of the coffer dam, another skiff scudded out across the lake, heading straight towards them. Macy had a bad feeling when she saw that Ursula Freye was at the tiller, but told Loris to slow down. If Ursula wanted something from her there would be no escape - she might as well get it over with now, in front of witnesses.

Ursula slowed too, drew alongside. Her blonde hair was tangled about her face and her gaze was bright and eager as she leaned forward and shouted to Macy across the narrow gap of water. 'I found something!

Something important! Meet me tonight! Eight o'clock! The place where we talked before!'

Before Macy could reply, Ursula gunned her skiffs reaction motor and the little boat raised its nose and drew a wide curve of white wake as it turned through one hundred and eighty degrees and skimmed past Macy's skiff again. 'Eight o'clock! It will change everything!' Ursula shouted as she went past, and then her skiff heeled hard and shot away.

Loris said, 'Do you want me to go after her?'

'Hell no,' Macy said. She was badly shaken by the encounter, by the wild look Ursula had given her, her wild words. The woman was obviously convinced that she had uncovered something that proved or supported her crazy idea that Emmanuel Vargo had been murdered, and although Macy definitely didn't want to have anything more to do with this fantasy she had a bad feeling, as physical as seasickness, that she was going to be dragged back into it anyway.

'You Brazilians sure like your alcohol. I bet someone's going to have a hangover tomorrow,' Argyll said, with a grin that reminded Macy that although he was twice her age, he was in many ways naive and oddly childlike.

They returned to the facility at the foot of the hollow strut and were eating supper and working up a full analysis of the reef sediment samples when Speller Twain walked in and told Argyll and Loris to get lost. Loris asked Macy if everything was all right; Speller Twain aimed his blank gaze at her and said that if it was all right with her he wanted to have a private conversation with Miz Minnot.

'Everything's fine,' Macy said. 'I'll see you tomorrow.'

After the two assistants had left, Loris giving Macy a troubled backward glance, Speller Twain said, 'You know what this about.'

The big man was leaning against the corner of a bench, flicking a magnifying screen on and off, on and off.

Macy said, 'I know you could ask Ursula what she's so excited about.'

'I could. But she is what she is, and you are what you are.'

'It must make you mad, not being able to touch her because she's consanguineous.'

'She thinks you're her friend,' Speller Twain said, moving his hand back and forth across the lighted screen, making shadows flutter across the struts high above. 'She'll tell you things she won't ever tell me. And you know that if you don't help me, I can have you pulled off the job right now and put in a hibernation coffin. And when they wake you back on Earth, that's where your real trouble will begin. But if you choose to help me find out where this leads, your exemplary work on behalf of the crew and the project won't go unrecognised.'

'If it leads anywhere.'