Suddenly she knew what she had to do.

She took her hand off the wheel, reached through the open window and poked him in the eye with a long-nailed forefinger. He let go and fell away, his hands covering his face. The distance between him and the jeep increased rapidly. Lucy realised she was crying like a baby. Two miles from her cottage she saw the wheelchair.

It stood on the cliff top like a memorial, its metal frame and big rubber tyres impervious to the unending rain. Lucy approached it from a slight dip, and saw its black outline framed by the slate-grey sky and the boiling sea. It had a wounded look, like the hole left by an uprooted tree or a house with broken windows; as if its passenger had been wrenched from it. She recalled the first time she had seen it in the hospital. It had stood beside David's bed, new and shiny, and he had swung himself into it expertly and swished up and down the ward, showing off. "She's light as a feather-made of aircraft alloy," he had said with brittle enthusiasm, and sped off between the rows of beds. He had stopped at the far end of the ward with his back to her, and after a minute she went up behind him and she saw he was crying. She had knelt in front of him and held his hands, saying nothing. It was the last time she had been able to comfort him. There on the cliff top, the rain and the salt wind would soon blemish the alloy, and eventually it would rust and crumble, its rubber perished, its leather seat rotted away. Lucy drove past without slowing.

Three miles further on, when she was halfway between the two cottages, she ran out of petrol.

She fought down the panic and tried to think rationally as the jeep shuddered to a halt.

People walked at four miles an hour, she remembered reading somewhere. Henry was athletic, but he had hurt his ankle, and even though it seemed to have healed rapidly, the running he had done after the jeep must have hurt it. She must be a good hour ahead of him, she calculated.

(She had no doubt he would come after her; he knew as well as she did that there was a wireless transmitter in Tom's cottage.)

She had plenty of time. In the back of the jeep was a half-gallon can of fuel for just such occasions as this. She got out of the car, fumbled the can out of the back and opened the tank cap.

Then she thought again, and the inspiration that came to her surprised her by its fiendishness.

She replaced the cap and went to the front of the car. She checked that the ignition was off and opened the bonnet. She was no mechanic but she could identify the distributor cap and trace the leads to the engine. She lodged the fuel can securely beside the engine block and took off its cap.

There was a spark plug wrench in the tool kit. She took out a plug, checked again that the ignition was off, and put the plug in the mouth of the fuel can, securing it there with tape. Then she closed the hood.

When Henry came along he was certain to try to start the jeep. He would switch on, the starter motor would turn, the plug would spark and the half-gallon of petrol would explode.

She was not sure how much damage it would do, but she felt certain it would be no help.

An hour later she was regretting her cleverness.

Trudging through the mud, soaked to the skin, the sleeping child a dead weight over her shoulder, she wanted nothing more than to lie down and die. The booby trap seemed, on reflection, dubious and risky: gasoline would burn, not explode; if there was not enough air in the mouth of the can it might not even ignite; worst of all, Henry might suspect a trap, look under the bonnet, dismantle the bomb, pour the petrol into the tank and drive after her.

She contemplated stopping for a rest but decided that if she sat down she might never get up again.

She should have been in sight of Tom's house by now. She could not possibly have got lost even if she had not walked this path a dozen times before, the whole island just was not big enough to get lost on.

She recognised a thicket where she and Jo had once seen a fox. She must be about a mile from Tom's home. She would have seen it, except for the rain.

She shifted Jo to the other shoulder, switched the shotgun from one hand to the other, and forced herself to continue putting one foot in front of the other.

When the cottage finally became visible through the sheeting rain she could have cried with relief. She was nearer than she thought-perhaps a quarter of a mile.

Suddenly Jo seemed lighter, and although the last stretch was uphill-the only hill on the island-she seemed to cover it in no time at all.

"Tom!" she called out as she approached the front door. "Tom, Tom!" She heard the answering bark of the dog.

She went in by the front door. "Tom, quickly!" Bob dodged excitedly about her ankles, barking furiously. Tom couldn't be far away; he was probably in the outhouse. Lucy went upstairs and laid Jo on Tom's bed.

The wireless was in the bedroom, a complex-looking construction of wires and dials and knobs. There was something that looked like a Morse key; she touched it experimentally and it gave a beep. A thought came to her from distant memory, something from a schoolgirl thriller-the Morse code for S.O.S. She touched the key again: three short, three long, three short.

Where was Tom?

She heard a noise, and ran to the window. The jeep was making its way up the hill to the house.

Henry had found the booby trap and used the petrol to fill the tank. Where was Tom?

She rushed out of the bedroom, intending to go and bang on the outhouse door, but at the head of the stairs she paused. Bob was standing in the open doorway of the other bedroom, the empty one.

"Come here, Bob," she said. The dog stood his ground, barking. She went to him and bent to pick him up. Then she saw Tom.

He lay on his back, on the bare floorboards of the vacant bedroom, his eyes staring sightlessly at the ceiling, his cap upside down on the floor behind his head. His jacket was open, and there was a small spot of blood on the shirt underneath. Close to his hand was a crate of whisky, and Lucy found herself thinking irrelevantly, I didn't know he drank that much. She felt his pulse.

He was dead.

Think. think.

Yesterday Henry had returned to her cottage battered, as if he had been in a fight. That must have been when he killed David. Today he had come here, to Tom's cottage, "to fetch David," he had said. But of course he had known David was not there. So why had he made the journey? Obviously, to kill Tom. Now she was completely alone.

She took hold of the dog by its collar and dragged it away from the body of its master. On impulse she returned and buttoned the jacket over the small stiletto wound that had killed Tom. Then she closed the door on him, returned to the front bedroom and looked out of the window.

The jeep drew up in front of the house and stopped. And Henry got out.

Lucy's distress call was heard by the corvette.

"Captain, sir," said Sparks. "I just picked up an S.O.S. from the island."

The captain frowned. "Nothing we can do until we can land a boat," he said.

"Did they say anything else?"

"Not a thing, sir. It wasn't even repeated."

"Nothing we can do," he said again. "Send a signal to the mainland reporting it. And keep listening."

"Aye, aye, sir."

It was also picked up by an MI8 listening post on top of a Scottish mountain. The R/T operator, a young man with abdominal wounds who had been invalided out of the RAF, was trying to pick up German Navy signals from Norway, and he ignored the S.O.S. However, he went off duty five minutes later, and he mentioned it to his commanding officer…

"It was only broadcast once," he said. "Probably a fishing vessel off the Scottish coast-there might well be the odd small ship in trouble in this weather."