So it was, at the nape of the neck. Rebus patted his head with his free hand. The back of his head was crispy, like strands of breakfast cereal. And something else: it was hurting like blazes.

They were at the bottom of the stairs now. Rebus dumped Steele on to the floor then straightened up. There was a tidal sound in his ears, and his eyes fogged over for a moment. His heart was thumping in sympathy with the rock music. I'll get a knife from the kitchen,' he said. Entering the kitchen, he saw that the back door was wide open. There were noises from outside, shouts, but indistinct. Then a figure stumbled into view. It was Moffat. He was holding both hands to his nose, covering the nose like a protective mask. Blood was pouring down his wrists and chin. He lifted the mask away to speak.

'The bastard butted me!' Flecks of blood flew from his mouth and his nostrils. 'Butted me!' You could tell he thought it wasn't fair play.

'You'll live,' said Rebus.

'The sergeant's gone after him.'

Rebus pointed to the hall behind him. 'Steele's in there. Find a knife and cut him loose, then both of you get out.' He pushed past Moffat and out of the back door. Light from the kitchen flooded the immediate scene, but beyond that was darkness. He'd dropped his torch up in the bedroom, and now cursed the fact. Then, eyes adjusting to the changing light, he ran across the small clearing and into the forest beyond.

More haste, less speed. He moved carefully past trunks and bushes and saplings. Briars tugged at him, but they were a minor nuisance. His main worry was that he didn't know where he was heading. The ground was sloping upwards, that much he could tell. As long as he kept moving upwards with it, he wouldn't be chasing his own tail. His foot caught on something and he fell against a tree. The breath left him. His shirt was wringing wet, his eyes stinging from a mixture of recent smoke and present sweat. He paused. He listened.

'Jack! Don't be stupid! Jack!'

It was Knox. Up ahead. A good distance ahead, but not impossible. Rebus took a deep breath and started walking.

Miraculously, he came out of the forest and into a larger clearing. The slope seemed steeper here, the ground sprawling with bracken and gorse and other low spiky plants. He caught a sudden flash of light: Knox's torch. Way over to the right of him and slightly uphill. Rebus began jogging, lifting his legs high to avoid the worst of the undergrowth. All the same, something kept tearing at his trouser-legs and his ankles. Stinging and scratching. Then there were patches of short grass, areas where quicker progress was possible – or would have been possible if he'd been fitter and younger. Ahead of him, the torch moved in a circle. The meaning was clear: Knox had lost his quarry. Instead of continuing to head for the beam of light, Rebus swung away from it. If it were possible for only two men to fan out, then that's what Rebus was trying to ensure they did, widening the arc of the search.

He came to the top of the rise, and the ground levelled out. He got the feeling that in daytime it would make a bleak picture. There was nothing here but stunted wilderness, hardly fit for the hardiest sheep. Way ahead a shadow rose into the sky, some hill range or other. The wind, which had dried his shirt but chilled him to the marrow, now dropped. Jesus, his head was hurting. Like sunburn but a hundred times worse. He stared up at the sky. The outlines of the clouds were visible. The weather was clearing. A sound had replaced the whistling of the wind in his ears.

The sound of running water.

It grew louder as he moved forwards. He had lost Knox's torchlight now, and was conscious of being alone; conscious, too, that if he strayed too far, he might not find his way back. A route wrongly taken could leave him heading towards nothing but hill and forest. He glanced back. The line of trees was still just about visible, though the house lights beyond were not.

'Jack! Jack!' Knox's voice seemed miles away. Rebus decided that he would skirt round towards it. If Gregor Jack was out there, let him freeze to death. The rescue services would find him tomorrow…

The running water was much closer now, and the ground beneath his feet was becoming rockier, the vegetation sparse. The water was somewhere below him. He stopped again. The shapes and shades in front of him… they didn't make sense. It was as if the land were folding in on itself. Just then, a huge chunk of cloud moved away from the moon, the large, nearly full moon. There was light now, and Rebus saw that he was standing not four feet from a sheer drop of five or six yards, a drop into a dark, twisting river. There was a noise to his right. He turned his head towards it. A figure was staggering forwards, bent over nearly double from exhaustion, its arms swinging loose and almost touching the ground. An ape, he thought at first. He looks just like an ape.

Gregor Jack was panting hoarsely, almost moaning from effort. He wasn't watching where he was going; all he knew was that he had to keep moving.

'Gregor.'

The figure wheezed, the head jerking up. It came to a stop. Gregor Jack rose to his full height, arching his head to the sky. He lifted his tired arms and rested his hands on his waist, for all the world like a runner at the end of his race. One hand went instinctively to his hair, tidying it back into place. Then he bent forwards and put his hands on his knees, and the hair flopped forwards again. But his breathing was becoming steadier. Eventually he straightened up again. Rebus saw that he was smiling, showing his perfect teeth. He began shaking his head and chuckling. Rebus had heard the sound before from people who'd lost: lost everything from their freedom to a big bet or a game of five-a-side. They were laughing at circumstance.

Gregor's laughter collapsed into a cough. He slapped at his chest, then looked at Rebus and smiled again.

Then sprang.

Rebus's instinct was to dodge, but Jack was moving away from him. And both of them knew precisely where he was headed. As his foot touched the last inch of earth, he leapt out into the air, jumping feet first. A couple of seconds later came the sound of his body hitting the water. Rebus toed his way to the edge of the rock and looked down, but the cloud was closing in again overhead. The moonlight was lost. There was nothing to see.

Making their way back to Deer Lodge, there was no need for Knox's torch. The flames lit up the surrounding countryside. Glowing ash landed on the trees as they made their way through the woods. Rebus ran his fingers over the back of his head. The skin was stinging. But he got the feeling shock might have set in: the pain wasn't quite so bad as before. His ankles stung too – thistles, probably. He'd run through what had turned out to be a field full of them. There was no one near the house. Moffat and Steele were waiting by Knox's car.

'How good a swimmer is he?' Rebus asked Steele.

'Beggar?' Steele was massaging his untethered arms. 'Can't swim a stroke. We all learned at school, but his mum used to give him a note excusing him.'

'Why?'

Steele shrugged. 'She was scared he'd catch verrucas. How's the head, Inspector?'

'I won't need a haircut for a while.'

'What about Jack?' Moffat asked.

'He won't be needing one either.'

They searched for Gregor Jack's body the following morning. Not that Rebus was there to participate. He was in hospital and feeling dirty and unshaven – except for his head.

'If you have a problem with baldness,' one senior doctor told him, 'you could always wear a toupee till it grows back. Or a hat. Your scalp will be sensitive, too, so try to keep out of the sun.'

'Sun? What sun?'

But there was sun, during his time off work there was plenty of it. He stayed indoors, stayed underground, reading book after book, emerging for brief forays to the Royal Infirmary to have his dressings changed.