He racked his brains. He couldn't be expected to come up with everything himself. Bohrmann's contemplations on submersibles would strike the right note. He cleared his throat. 'Of course we could have sent a robot down,' he said, 'but it wouldn't be the same. I've seen plenty of video images – footage recorded by robots. Incredible stuff Hmm, how did the next bit go? 'But actually sitting in the submersible, being down there on the seabed, seeing it all in 3-D – it's hard to imagine. There's nothing quite like it. And, er, besides… besides, there's no doubt that it gives us an, er, a better view – better insight into what's going on down there and, uh, what we can do to help.'

'Amen,' said Alban, softly, in the background.

Stone turned round, crawled beneath the submersible, and scrambled through the hatch. The pilot reached over, but Stone ignored the helping hand, pulled himself up and sat down. It was a bit like being in a helicopter. The weirdest thing was the sensation that he was still outside. The only difference was that he couldn't hear the bustle on the deck. The acrylic bubble was several centimetres thick and hermetically sealed.

'Do you want me to go over anything again?' Eddie enquired.

'No.' Eddie had shown him the ropes earlier, in his characteristically thorough, unflappable way. Stone glanced at the small computer console in front of them. His right hand slid down to touch the controls on the side of his seat. On the deck outside the photographer was taking pictures and the cameraman was filming.

'Great,' said Eddie. 'Let the fun begin.'

The submersible was jolted sideways. Suddenly they were suspended above the deck, gliding over it, until the choppy sea appeared below. There was quite a swell. For a moment they hung motionless. Then Alban gave the thumbs-up. Stone nodded at him. Over the next few hours they'd communicate via underwater telephone. There wouldn't be any optical fibre between the submersible and the ship; just sound waves. As soon as the boom released them, they'd be out there on their own.

Stone's stomach churned.

There was another jolt, then a clunk above them as the cable was released. The submersible sank down, rose on a wave, then water flooded into the tanks as Eddie opened the valves. The Deep Rover sank like a stone, descending thirty metres every minute. Apart from two positioning indicators on the battery pods, all the lights were switched off. Saving power was vital: they would need it later.

There were barely any fish to be seen. After a hundred metres the deep blue water darkened to a silky black.

On the other side of the hull something flashed, like a firecracker. One flash at first; then more.

'Luminescent jellyfish,' said Eddie. 'Pretty cute, huh?'

Stone was fascinated. He'd done a few dives before, but never in a Deep Rover. It really did feel as though nothing separated them from the sea. Even the red flashes from the lights on the console seemed at one with the shoals of glowing organisms outside. The thought of building a processor in this alien universe suddenly seemed so absurd that he almost laughed out loud.

While the submersible sank, the air inside it grew cooler, but it was perfectly pleasant. In comparison to Alvin, MIR or Shinkai, which could go down to six thousand metres, the Deep Rover's system of temperature regulation was luxurious. To be on the safe side, Stone had worn a warm jumper and a pair of thick socks – shoes weren't allowed in submersibles to protect the instruments from accidental kicks. Eddie looked focused, but relaxed. Now and then a noisy voice came through the loudspeaker: technicians calling to check on them. You could hear the words but the sound was distorted as it mingled with thousands of other noises in the sea.

They were falling and falling.

After twenty-five minutes Eddie turned on the sonar. The sphere was filled with a soft whistling and clicking, mixed with the gentle hum of the electrics.

They were approaching the seabed.

'Popcorn and drinks at the ready,' said Eddie. 'It's show-time.'

He switched on the floodlights.

GULLFAKS C, Norwegian Shelf

Lars Jörensen stood on the top platform of the metal staircase that led from the helipad to the accommodation module below and gazed down at the derrick, his arms resting on the rails. The white tips of his moustache quivered in the wind. On clear days the derrick seemed in touching distance, but now it was retreating out of sight. As the mist from the approaching storm thickened, it seemed more illusory by the hour, as though it were trying to disappear entirely and fade into memory. Since Lund's last visit, Jörensen had lapsed into melancholy. He kept wondering what Statoil might be planning for the slope. It had to be an automated system. Maybe they'd use a production vessel too… Lund had obviously thought she'd succeeded in fobbing him off, but Jörensen wasn't stupid. He could even appreciate why they were doing things as they were. After all, it made sense to save labour by swapping people for machines. Machines didn't require nice hot meals. They didn't sleep, they worked in hostile environments and they didn't expect to be paid. They never complained, and if they were getting on a bit, you could throw them away without having to provide for them. But robots couldn't respond intuitively or provide an adequate replacement for human eyes and ears. If you took away the humans you avoided human failure, but if the machinery stopped working without humans to fix it… It made him think of the disaster movies he watched on late-night TV, when the sea outside was crashing on the platform. Man would be powerless to act. Machines had no regard for life and the natural world around them. They didn't care about the welfare of their creators, who'd chosen to exclude themselves from the design. Humanity and compassion were absent in a robot.

Little by little the light was fading. The sky turned a deeper shade of grey as the drizzle set in. What a foul day, thought Jörensen.

For some time now the sea had smelt as though it was full of chemicals and, to make matters worse, the weather was even gloomier than his mood. We're working on a wreck, he thought, a ghost town in the water, filled with zombies. When the oil ran out, a skeleton without purpose would remain. The oil-workers were being laid off, the platforms discarded, and the future of the industry was a picture on a screen – video footage from a world they couldn't reach, no matter what went wrong.

Jörensen sighed.

In the old days, he thought, there had been the magical moment when men flung their arms round each other, dripping with shiny black oil, a fountain cascading from the sandy ground beside them, promising riches beyond their wildest dreams. Like with James Dean in Giant. Jörensen loved that film. To him, the scene where Dean struck oil was far better than the one in Armageddon, even though Bruce Willis was on a real oil-rig and Dean in the Texan desert. Watching the oil-spattered Dean laugh and jump around reminded him of sitting on his grandfather's knee, listening to stories of when he was young and everything was better.

Now he was a grandfather too.

Just a few more months, Jörensen told himself, and he'd be gone. Finished. Past it. He was luckier than the youngsters, though. No one was going to streamline him out of existence: he'd leave of his own accord, and get a pension with it. He felt almost guilty about clearing off before the oil platforms' final hour. But it wouldn't be his problem. He'd have other things to think about.

He heard a noise approaching from the distant coast. The rhythmic throbbing grew louder, becoming the roar of a helicopter. Jörensen craned his neck. He knew all the helicopters that flew around here. Despite the distance and the poor visibility he spotted a Bell 430 pass over Gullfaks and disappear into the mist. The beat of the rotors quietened to a hum and eventually fell silent.