A final gust shook the Bell 430, then the skids touched down. The helicopter landed with a jolt.

'Well, that wasn't too bad, was it?' said the pilot.

Johanson saw a small figure standing at the edge of the landing field, her hair blowing in the wind. Karen Weaver, he guessed. A few metres away from her, a motorbike was propped up on its stand. He stretched, then slid Whitman's poetry back into his bag and picked up his coat. 'It would have been fun to do a few more laps,' he said, 'but I'd have to keep the lady waiting.

Can you come back for me tomorrow around lunchtime? Twelve o'clock, let's say.'

'No problem.'

He waited for the door to slide open, then clambered down the ladder. He was pleased to be back on firm ground. The pilot had to head off again, but turbulent conditions were clearly part of the job. He'd take a short break, then carry on to Lerwick for fuel. Johanson swung his bag over his shoulder. His coat billowed in the wind and flapped around his legs, but at least it wasn't raining. Karen Weaver came to meet him. It was strange, but with every step her size diminished. By the time she was standing in front of him, he guessed she was barely five foot five. She was nicely compact. Her jeans were stretched over muscular legs, and her strong shoulders stood out beneath her leather jacket. As far as Johanson could tell, she wasn't wearing makeup. Her skin glowed with a natural tan and freckles were scattered over her forehead and wide cheekbones. The wind tugged at a cascade of auburn curls. She eyed him inquisitively. 'Sigur Johanson,' she announced. 'How was your flight?'

'Wretched. Thankfully I had Walt Whitman to reassure me.' He glanced back at the helicopter.

She smiled. 'Shall we go for some food?'

'Sure. Where?'

She nodded in the direction of the motorbike.

'We could drive into town. If you managed the flying, you won't mind the Harley. It'd be quicker to eat at the station, though – if corned beef and pea soup don't put you off.

Johanson noticed that her eyes were an unusually brilliant blue. 'Why not?' he said. 'Where are all your scientists? Out sailing?'

'No, it's too rough. They headed into town for supplies. They don't mind me doing what I like here, including helping myself to their tins. That's about the extent of my cooking.'

Johanson followed her over the gravel towards the station. The buildings didn't look quite as flimsy from this angle as they had from above. 'Where are the boats?' he asked.

'We don't like leaving them out.' She pointed to the building closest to the water. 'The bay isn't very sheltered, so once we've finished we lug them back to that hut by the sea.'

The sea…

Where was it?

Johanson did a double-take and stopped. A few seconds earlier breakers had been crashing up the beach, but now there was nothing but mud and rocks. Within the last minute the tide had receded, leaving the seabed exposed.

It was impossible for the tide to turn so quickly. The water had retreated by hundreds of metres.

Weaver turned. 'What's wrong?'

He shook his head. He could hear noise. At first he thought it was an aeroplane swooping towards the shore. But it didn't sound like an aeroplane, more like a roll of thunder, only thunder rose and fell, and this noise just kept…

Suddenly he knew what it was.

Weaver had followed his gaze. 'What the hell-'

Johanson saw the horizon darken. 'To the helicopter,' he yelled.

Weaver seemed rooted to the spot. Then she darted forwards. Together they ran towards the helicopter. Through the bubble of the cockpit Johanson saw the pilot checking the instruments. It was a moment before he noticed the figures dashing towards him. He stopped what he was doing. Johanson signalled for him to let down the ladder. He knew the pilot couldn't see what was approaching from the water, since the helicopter was facing inland.

The man frowned, then nodded. With a hiss the door slid open and the ladder was lowered.

The thundering drew closer. Now it sounded as though the whole world was in motion, rushing towards the beach.

Which was exactly what was happening, thought Johanson.

Wrong place, wrong time.

Torn between terror and fascination, he paused at the foot of the ladder and watched as the sea returned, flooding over the muddy plain.

Johanson!'

He pulled himself together and hurried up the steps, Weaver at his heels. He saw the confusion in the pilot's eyes and shouted, 'Start her up. Hurry.'

'What's that noise? What's going on?'

Just get this thing in the air.'

I'm not a magician, you know! What the hell's going on? Where am I supposed to go?'

'Anywhere. So long as it's up.'

The rotors rattled into action. The Bell wobbled and took off, climbing one metre, two. Then the pilot's curiosity conquered his fear, and he swung the helicopter through 180 degrees so that they were looking at the sea. 'Holy shit,' he gasped.

'Look!' Weaver was pointing towards the huts. 'Over there.'

Someone had come out of the main building and was running towards them. A man in jeans and a T-shirt. Weaver stared at him in horror. 'We've got to go down. Oh, God! I swear I didn't know Steven was here – I thought they'd all-'

Johanson shook his head. 'He won't make it.'

'We can't leave him here.'

'Look outside, for Christ's sake, he's not going to make it. If we go down none of us will.'

Weaver headed for the door as the pilot steered sideways over the strip of sand towards the man. The helicopter twisted, buffeted by strong blasts and for a moment they lost sight of the man, then they were almost above him.

'We've got to go down!' shouted Weaver.

'No,' said Johanson.

She didn't hear him. Even the sound of the rotors was lost in the thunder of the wave. Johanson knew it was too late to save the man now, but precious moments had been wasted, and he wasn't sure that they could get away themselves. He forced himself to look away from the running scientist and focus ahead.

The wave must have been thirty metres tall, a vertical wall of dark water. It was still several hundred metres from shore, but it was coming towards them at the speed of an express train. They had just seconds to get clear. The pilot made one last attempt to get closer to the fleeing man. Maybe he was hoping that the guy could leap through the open door or clutch on to one of the skids like a movie stunt-

The scientist stumbled, and fell.

Darkness descended in front of them. There was no sign of the sky through the cockpit screen, just the wall of water. It filled their view, surging forwards at incredible speed. They'd missed their chance. There was nowhere for them to go. Flying upwards, they'd be caught in the middle of the gigantic wave. By flying inland, they could buy themselves time, but the wave would still catch them. The tsunami was faster and, besides, they were facing the wrong way. The pilot couldn't turn the helicopter now.

Johanson's mind disengaged, and he wondered how he could bear to look at the vertical front of water without going mad. Then reality caught up with him. The pilot took the only viable option and sent the helicopter shooting backwards and up. The nose of the Bell sank down. For a second the ground was visible through the cockpit, but they didn't sink towards it; they were flying up and backwards, away from the wave that was racing into shore. The Bell roared as though its gearbox was about to explode. Johanson would never have thought that a helicopter was capable of a manoeuvre like that. Maybe the pilot had never believed it either. But it worked.

The breaking wave hit the beach, and collapsed. Mountains of spray shot up towards the Bell as it continued its lunatic flight. The tsunami bellowed and screeched. The next minute a tremendous jolt shook the aircraft and Johanson was slammed against the side, right next to the open door. Water slapped into his face. His head banged backwards, and red flashes passed before his eyes. His fingers clutched a strut, and tightened. Pain surged through him. He could no longer tell whether the booming was coming from the wave or his head; whether they were going up or down. His only thought was that the wave had finally done for them and they were about to be dashed to pieces. He waited for the end.