'No. Have you?'

'A few times.' Eddie shrugged. 'There's bugger-all to see, though. It's just like here. The light's more my thing.'

'So you don't want to try for the record, then?'

'There's no point. Jacques Piccard made it to 10,740 metres and, sure, scientifically speaking, it was a breakthrough, but there'd have been nothing to look at.'

'How do you know?'

'I don't. I just can't believe there would be. I mean, the abyssal plains aren't especially interesting. I like to see the benthos.'

'Didn't Piccard get to 11,340 metres?'

'Oh, that old chestnut.' Eddie laughed. 'That's what they say in all the books, but it's wrong. A discrepancy on the depth gauge. It was calibrated in Switzerland for freshwater usage, and fresh water's not as dense. So the one and only time they took a sub to the deepest spot in the ocean, they measured the depth wrong. Now if they'd-'

'Look. Over there!'

The beam of light in front of them was swallowed by darkness. As they drew closer they could sec that the seabed dropped off abruptly. The light was lost in the abyss.

'Stop here.'

Eddie's fingers flew over the controls. He counterbalanced the thrust, and the Deep Rover came to a halt. Then it started to spin.

'Current's pretty strong here,' said Eddie. The submersible kept turning until the floodlights lit the edge of the precipice. 'Looks like something caved in, not long ago either. I'd say it's pretty fresh.'

Stone's eyes roamed around nervously. 'Any clues from the sonar?'

'There's a drop of at least forty metres. Can't tell what's on the other side.'

'You mean the plateau-'

'There is no plateau. It's fallen through.'

Stone chewed his lip. They had to be really close to the processor now. But there hadn't been a precipice here last year. Then again, it probably hadn't been there a few days ago either.

'Let's go down,' he decided. 'We'll take a look at where it goes.'

The Deep Rover gathered speed and sank down over the precipice. It was only a couple of minutes before the seabed emerged in the floodlights. It looked like a bomb site.

'We need to ascend a few metres,' said Eddie. 'Those crevices look nasty. We could easily fall down.'

'Sure, just a sec- Shit! Straight ahead.'

A torn pipe, one metre in diameter, came into view. It ran diagonally across enormous chunks of stone and disappeared beyond the floodlights. Thin black threads of oil were rising from it, climbing towards the surface in taut columns.

'It's a pipeline!' Stone was appalled. 'Oh, God.'

'It used to be a pipeline,' said Eddie.

'Let's follow it.' Stone knew where the pipeline would lead – or, rather, where it originated. They were on the site of the unit.

But the processor was gone.

A fissured wall loomed ahead. Just in time Eddie jerked the submersible up. The wall seemed to extend forever, but soon they were up and over it with just centimetres to spare. It was only then that Stone realised it wasn't a wall: it was a vast expanse of seabed, rising vertically through the water. Beyond it, there was another steep drop. Particles of sediment drifted through the beam of light, clouding their vision. Then the floodlights caught a stream of bubbles shooting frantically towards the surface, spraying from the gaping edges of a hole. 'Holy shit,' whispered Stone. 'What happened here?'

Eddie banked to avoid the column of bubbles. For a moment they lost sight of the pipeline, then it pushed its way back into the light. It led downwards.

'Damned current,' said Eddie. 'It's pulling us into the blow-out.'

The Deep Rover spun.

'Keep following the pipeline,' commanded Stone.

'That's madness. We need to ascend.'

'The processor's right here,' insisted Stone. 'We'll see it any second now.'

'Like hell we will. There's nothing left to see.'

Stone was silent. Ahead, the pipeline curved upwards, as if it had been uprooted by a giant hand. It ended in a twisted stump, the warped steel curled in weird-looking sculptures.

'Still want to go on?'

Stone nodded. Eddie manoeuvred the submersible alongside the pipe. For a moment they hovered above the serrated opening, as though in the clutches of a gaping maw.

'Any further and there'll be nothing beneath us at all,' said Eddie.

Stone clenched his fists. Alban had been right. They should have sent a robot first In that case, giving up now would be truly absurd. He needed to know what had happened. He had no intention of returning to Statoil without a full report. He refused to let himself be humiliated again by Skaugen.

'Keep going, Eddie.'

'You're crazy.'

On the other side of the twisted pipe, the fissured seabed slanted steeply downwards. The clouds of sediment thickened. Now the strain was telling on Eddie too. At any moment a new obstacle might appear in their path.

Then they saw the processor.

In fact, all they could see were some struts, but Stone knew right away that the Kongsberg prototype was gone, buried under the rubble of the broken plateau, more than fifty metres deeper than it had originally been built.

He peered closer. Something detached itself from the metal struts and came towards them.

Bubbles.

It reminded Stone of the colossal vortex of gas that they'd seen on the Sonne- of the blow-out when the video-grab had plunged through the hydrates.

Suddenly he was filled with panic. 'Move!' he yelled.

Eddie released the remaining weights. The submersible jerked upwards and shot through the water, followed by the vast bubble. Then the maelstrom engulfed them and they fell back down. 'Shit!'

'What's going on down there?' It was the tinny voice of the technician on the Thorvaldson. 'Eddie? Answer me! We've got some funny readings up here. A whole load of gas and hydrates is surfacing.'

Eddie pressed the transmission button. 'I'm throwing off the outer hull. We're on our way up.'

'What's the matter? Are you-'

The voice of the technician was drowned by hissing and banging.

Eddie had blasted off the battery pods and sections of the hull. It was a last-ditch attempt to lose weight. The Deep Rover, minus its batteries and exostructure, started to spin and rise again. Then a powerful jolt shook it. Stone saw a rock appear beside him, a gigantic slab of seabed had catapulted upwards. Inside the capsule, things turned upside down. He heard the pilot scream as they were hit again, from the right this time, pushing them out of the blow-out. The Deep Rover instantly gathered speed and shot up. Stone clung to the armrests, practically lying in his seat. Eddie sagged towards him, eyes closed, blood running over his face. Stone realised with horror that now it was up to him. Frantically he tried to remember how to stabilise the submersible. He could switch the controls from Eddie to himself.

Eddie had shown him how to do it. It was that button there.

Stone pressed it, trying at the same time to push Eddie away from him. He wasn't sure that the thrusters would work now that the outer hull was gone. The numbers were whizzing past on the depth gauge, so he knew the submersible was still rising fast. In the end it didn't matter which direction they were heading in, so long as it was up – thank God there was no need to worry about decompression problems: the pressure in the capsule was kept at surface level.

A warning light flashed on.

The floodlights above the right-hand tank went out, then all the other lights. Stone was plunged into darkness.

He was shaking.

Calm down, he told himself Eddie showed you the emergency power supply. It's one of the buttons on the top row of the control panel. It either turns itself on or you have to do it manually. His fingers felt for the panel in the darkness.

What was that?