'So the hypervariable sections allow them to learn?' asked Crowe.

'Yes and no,' said Weaver, glancing at her notes. 'It's theoretically possible, but on the computer it takes too long. The mass of jelly that attacked us on the well deck was incredibly quick to respond, and it probably thinks just as swiftly. It's a superconductive organism, an enormous variable brain. It didn't make sense to limit ourselves to small segments of DNA. We programmed the entire strand so it was capable of learning, and that increased the speed of cognition enormously.'

'Leading to what?' asked Li.

'We can only base our conclusions on the few trials that we ran before the meeting, but we've already seen enough to be sure of a few things: yrr-collectives, no matter what their size, think at the speed of the most up-to-date parallel processors. The information held by individual cells is standardised, and new data gets scrutinised. We found some of the collectives weren't able to handle new challenges, but as they aggregated, they learned. Initially, the learning curve was linear, but beyond a certain point, the collective's behaviour couldn't be predicted-'

'Hold on.' Shankar interrupted her. 'Do you mean to say that the program takes on a life of its own?'

'We introduced entirely new situations. The more complex the problem, the more frequently the amoebas aggregated. It didn't take them long to develop strategies that hadn't been programmed. They started to work creatively. They became inquisitive. And they learned exponentially. We only had time to do a few tests, and it's only a computer program, but our electronic yrr learned to assume any given form – to imitate and vary the shapes of other living things. They were able to form feelers that made our fingers seem no more sensitive than cudgels. They examined objects on a nano level. And every single one of their experiences was shared with every single cell. They solved problems that would leave us stumped.'

For a moment there was silence as the news sank in. It was clear from their faces that they were remembering the scenes on the well deck. In the end Li said, 'Give me an example of a problem.'

Anawak nodded. 'Let's say I'm a yrr-collective. I've managed to infest an entire continental slope with worms that I'd previously bred, packed with bacteria and transported across the seabed. I want them to destroy the hydrates along the length of the slope, but there's one small problem: although the worms and the bacteria are causing a hell of a lot of damage, they can't start the landslide without help.'

'That's right,' said Johanson. 'We still haven't figured that out. The worms and the bacteria take care of the groundwork, but a little something's still missing before the catastrophe can unfold.'

'A little something like, for instance, a small drop in the water level, hence decreased pressure on the hydrates, or maybe an increase in the water temperature near the continental slope – right?'

'Exactly.'

'Let's say one degree Celsius?'

'That would probably do it, but I'd say two to be sure.'

'OK. Well, we did our homework. The Hakon-Mosby mud volcano is situated not far from the Norwegian continental slope at a depth of twelve hundred and fifty metres. Gas, water and sediment are vented from inside the earth to the surface of the seabed. The water around a mud volcano isn't hot, but it's warmer than elsewhere. So what do I do? I aggregate until I'm an enormous yrr-collective. Then I turn myself into a funnel, and since I need to be an extremely long funnel, I limit the width of my walls to several cells across. I need huge quantities of myself-billions and billions of cells – but I extend over several kilometres. My circumference matches that of the volcano's main crater – around five hundred metres. It allows me to draw warm water from the volcano, so I'm like an enormous pipe, transporting the water to the site where the worms and the bacteria have been burrowing away. And then, whoosh, the slope collapses. Incidentally, I can use the same method for warming the water near Greenland and around the poles to melt the icecaps and disable the Gulf Stream.'

'OK, but those are your computerised yrr,' Peak said skeptically. 'What can real yrr do?'

Weaver pursed her lips. 'That and a good deal more, at a guess.'

SWIMMING

Weaver's body was feeling the strain as much as her mind. As they left the operations room, she asked Anawak if he felt like a dip in the pool. Her shoulders were one long ridge of pain – even though her body was accustomed to being put through its paces. None of the training she'd subjected herself to had prepared her for this. Maybe that's your problem, she told herself You should probably take up a sport that isn't a feat of endurance.

Anawak went with her. They stopped off at their cabins to change into swimwear, then set off to the pool together, wrapped in towelling robes. Weaver felt like holding Anawak's hand – in fact, that wasn't all she felt like doing, but she had no idea how people initiated that kind of thing without embarrassing themselves. Before the radical turnaround in her life, she'd taken anyone and everyone who came her way, but love had never entered the equation. Now she felt shy and inhibited. She didn't even know how to flirt. How were they supposed to end up in bed together, when only last night people had died and the whole world was on the brink of disaster?

Why did she have to make it such a big deal?

The Independence's swimming-pool looked surprisingly welcoming for a warship. It was the size of a small lake. As her robe slid off her shoulders, she felt Anawak's gaze on her back. Suddenly it occurred to her that it was the first time he'd seen her like that. Her swimsuit had high-cut legs with a low, scooped back and, of course, her tattoo was on display.

She walked self-consciously to the edge, took off and arced elegantly through the air. Arms stretched in front of her, she cut through the water, just below the surface. She heard Anawak swim up behind her. Maybe it would happen here, she thought. Half hoping and half fearing that he would catch up with her, she kicked her legs and sped away.

Coward. Why shouldn't she just do it?

Dive down and make love in the pool.

Bodies uniting in the water…

The idea came to her in a flash.

It was laughably simple and more than a little irreverent but, assuming it worked, it was brilliant. It was a peaceful way of persuading the yrr to retreat – or, at least, to reconsider.

Her fingertips brushed against the tiled side. She stood up and wiped the water from her eyes. The idea seemed almost obscene, and with every metre that Anawak swam towards her, she felt less and less certain.

She'd have to sleep on it.

Suddenly he was very close.

She pushed up against the side of the pool, chest heaving, heart pounding, just as it had all those years ago in the icy waters of the Channel.

She felt his hands round her waist. Her lips opened.

A rush of fear.

Say something, she told herself. There must be something you can say. Something – anything-

'Sigur's feeling better.'

The words lurched out like toads and she saw the disappointment in his eyes. He drifted away from her and slicked back his wet hair. 'Yeah.'

How could she have been such an idiot?

'But something else is bothering him. A problem.' She rested her elbows on the side of the pool and pulled herself up. 'Keep it to yourself, though. I don't want him to think I go around telling everyone. I just wanted your opinion.' Sigur's got a problem? She was the one with the problem!

'What kind of problem?' asked Anawak.

'He saw something odd. Or, at least, he thinks he did. And from what he said, I believe him. But then it makes you wonder what it means, and… Well, it's like this…'