Cooper opened his mouth to ask whether that meant people who believed in the paranormal were mad, but Sinclair shook his head.

‘No, supernatural experiences aren’t themselves a symptom of mental illness. But people with different views of reality or unusual opinions have always held a rather complex role in society. Some are considered mad, while others are treated as prophets and visionaries. At the end of the day, the difference comes down to a question of contemporary social attitudes.’

‘You seem to be suggesting that almost anyone might suffer from psychosis of some kind.’

Sinclair closed the clasps on his briefcase with a click. ‘Well, it has been argued that patients with psychotic illness are simply at one end of a spectrum. Some practitioners say that psychosis is merely another way of constructing reality, and not necessarily a sign of illness at all. Only a small proportion of people who experience hallucinations are actually troubled by them.’

The psychiatrist smiled past Cooper, who turned to see Gavin Murfin hovering near the desk.

‘Well, I suppose police officers have to be feet-on-the-ground sort of people. No time for the imagination, eh? But most hallucinations are quite neutral, you know. They might simply take the form of a voice commenting on what you’re doing. People get used to that. In fact, for some individuals it’s rather comforting, as if they have a permanent, invisible companion, perhaps a loved one who’s died. Believe me, it’s not uncommon.’

‘I can imagine that.’

‘Well, now – instead of something neutral or reassuring, think of a voice that constantly makes negative comments about you and your actions. That’s the troubling sort of hallucination experienced by people in clinical groups, who need psychiatric help to deal with them. Treatment isn’t necessary unless the experience is disturbing.’

They walked down the corridor towards the stairs, passing the busy incident room on their way towards the reception area. By the front desk, the psychiatrist paused to shake hands. He held Cooper’s hand a little too long, giving him an appraising stare.

‘You know, many hallucinations occur in the phases of consciousness between waking and sleeping. You might hear your name being spoken, or get a feeling of someone being in the room, or of falling into an abyss. All of those are common. There’s a sort of paralysis that occurs in the hypnopompic stage just before waking – a sensation like a heavy weight on your chest that prevents you from moving or calling out for help.’

‘Oh, yes?’ said Cooper, wondering what he might be giving away by his expression.

Sinclair smiled reassuringly. ‘Generally, people write those experiences off as dreams, DC Cooper. They wake up. And then they get on with their lives.’

Cooper walked slowly back to the CID room, and found Murfin already at his desk, watching Fry heading towards him.

‘You know this voice that constantly makes negative comments about me and my actions,’ said Murfin.

Cooper looked up in surprise. ‘Yes, Gavin?’

‘It’s a relief to know it’s only a hallucination. I thought it was my DS.’

When Cooper had briefed her and left for the Heights of Abraham, Fry thought about John Lowther’s confusion of speech. He hadn’t seemed to mix up his words when she’d seen him on Wednesday – not the way he had later, when he was interviewed. He’d been more vague and confused than anything else. Dr Sinclair might be right. But it was rather more like a description someone else had given her recently.

Ignoring the glances of Cooper and Murfin, Fry picked up the phone and called Juliana van Doon at the mortuary.

‘Mrs van Doon, what would be the effects on a person who’d suffered only slightly from smoke inhalation?’

‘Mild hypoxia? Well, there might be effects on the voice. Coughing, hoarseness, stridor – that’s a high-pitched sound, like croup. You could look for singed eyebrows, moustache, or other facial hair. Also traces of soot in the nose or mouth, slight burns to the face.’

‘Yes, but what about their behaviour?’

‘Their behaviour?’ The pathologist hesitated. ‘This is just an informal opinion?’

‘Of course.’

‘Well, I’d say a person suffering from mild hypoxia would appear distracted, and probably clumsy in both their speech and manner. Is that what you were thinking of, Sergeant?’

‘Yes,’ said Fry, nodding gratefully. ‘That’s exactly what I was thinking of.’

32

He’d forgotten the other voices. Somehow, he’d managed to put them out of his mind, until they started to come back. It was so strange, the way the brain could shut out things that it didn’t want to know about, drawing curtains across the darkest corners, no matter how terrible the secrets that lay behind them.

These were the voices. The voices that told him to do things. He’d remembered them too late. Much too late.

John Lowther’s hands trembled as he drove his Hyundai down the A6. His palms felt slippery on the steering wheel, and the windows steamed up so badly that he had to turn the fan on full to clear the condensation from the windscreen. For a moment, he considered letting the glass stay steamed up and driving blind through Matlock, letting fate take its course. But in the next second, he knew the idea had come from one of his voices, whispered almost imperceptibly into his ear. His defensive measures were failing.

He switched on the radio, let the tuner find a music station, and turned up the volume. It was Peak FM, playing the Stones – ‘Paint it Black’. Perfect. He belted out the words along with Jagger as he passed through the square and over the bridge into Dale Road, oblivious to the stares and laughter of pedestrians when he halted in traffic. They couldn’t hear him, and all he could hear was the music. The best of all worlds.

In Matlock Bath, he crossed the Derwent and parked near the old railway station, with its little cowled chimneys, mock timbering and herringbone brickwork. Though the Derwent Valley line was still open to Derby, Matlock Bath’s ticket office and waiting room had been converted into a wildlife gift shop. From here, it was possible to walk across the track and follow a footpath to the cable car station.

He passed a compound full of spare cable cars. Actually, half cars. They looked as though they’d been cut open to reveal their interiors. The hum of motors and the creak of cables over wheels increased to a rapid whir as a string of cars swung out of their station, dipping and bobbing as they rose. Two strings passed each other high over the village, half-hidden by the trees. In the roof of the station building, a huge steel wheel turned the cables. He saw with relief that all the cars were empty. There wasn’t much business for the Heights of Abraham at this time of year, with the kids back at school.

Arriving at the Treetops Centre, he found a sign that said Where to go next. Good question. Near the High Falls shop were a woodland family, carved by someone with a chainsaw and power file. The elm girl, the daughter of the family, was a young sapling crowned by a giant squirrel clutching an acorn, waiting to chew her bones.

A narrow doorway gave access to the base of the Prospect Tower. Halfway up the steps, there was no light from the opening at the top, just the faint glow of a bulkhead light on the wall below the handrail. The outer stones were worn smooth by the feet of thousands of visitors, but the inner steps still bore the mason’s tool marks, where they were too narrow to walk on.

This tower had been built to take advantage of the views and provide work for the unemployed. But it also contained a rare thing – a true spiral staircase. There was no central column, and the steps tapered sharply, so they were only wide enough to walk on if you stayed close to the outside wall and clung to the rail.