‘Don’t be ridiculous,’ he said.

‘Oh, come on!’

They held onto one another, shrieking, and knackered in seconds. The children were delighted with the trampoline, and for a short time it was a highlight of any visit to the Jameson household. Then the girls were teenagers and uninterested in adult company, and the trampoline became rusted, and buried beneath each new autumn’s leaves.

The Gracie case came to him when he was fifty. January. He hadn’t worn a hat for many years. He and Alice had just returned from work and had taken down the Christmas decorations. Something about the act embarrassed him, although he had enjoyed them in December. The undressing of the tree; the careful placement of the ornaments back into their boxes. Who had it all been for? They sat down for dinner in the kitchen – Alice was talking about hospital politics, and their niece’s new boyfriend, and the grisliest trauma call of the day – and the phone started to ring.

He was summoned back to the office for the initial meeting. The forensic team had sent over photographs from the house, and the Detective Chief Superintendent guided them through each room: this is the body of the father; Boy D was discovered here, in a crib; Girl B and Boy B were in the first room upstairs, restrained. The forensic archaeologists had started digging in the garden and at the foundations of the house, but it would be a long exercise. The children were in different hospitals, according to their specific needs; they were all malnourished, and, with the exception of two of the boys, they were each in a critical condition.

Seven children. Jameson watched the pictures on the screen, changing and yet the same. Same soiled carpets, same dank mattresses, same bags of rot. He thought of Alice, who would be curled on the sofa, wearing her glasses to watch the television. ‘It sounds bad,’ she had said, as he left. ‘I’ll wait up.’

‘Don’t, Alice.’

‘I’d like to.’

There were two priorities, said the DCS. The first was the preservation of evidence; the second was the commencement of interviews. How did this happen? When were the children last seen; who were their friends; where were the other relatives? There would be medical reports tomorrow. They had the mother in custody. They had found an aunt, who seemed eager to talk.

‘We can’t speak to the children just yet,’ he said, and Jameson understood that this had been a point of contention and that the DCS had lost.

Jameson was asked to interview Peggy Granger. ‘After that,’ the DCS said, ‘you can work with Girl A. One of the child psychologists is already reading into her case. Dr Kay. Do you know her? Young. Very impressive – I’ve worked with her before. Groundbreaking, some people say.’

‘Girl A,’ Jameson said. ‘Is she the one who escaped?’

He returned home in the middle of the night. Alice was lying on the sofa in lamplight, with two cups of tea on the carpet beside her.

‘They always told me not to marry a policeman,’ she said. ‘And they were right.’

He knew that she would have been thinking of this all evening; calculating exactly what to say to make him smile. He lifted her legs up, then sat down and placed them onto his lap.

‘I feel a hundred years old,’ he said.

‘You look at least two hundred and seven. How was it?’

‘Terrible,’ he said. She reached down and handed him a mug. ‘And the villain’s already dead.’

‘I’m sorry,’ she said.

‘Do you remember,’ he said, ‘the evenings, very early on, when I would sometimes cry? I always thought that it was because of all of the terrible things that I had seen. All of the worst parts of the human race.’

‘Sh,’ she said. ‘You don’t—’

‘But it wasn’t,’ he said. ‘I think it was gratitude. I think that I was just so relieved. You see? For us, and this life.’

He came to know Dr Kay well over the months that followed. They spent many hours in the hospital, listening to the stories of the thin, wounded child. There were days when he found it difficult to look at her, and would focus instead on his notes, or the strange digital language of the hospital machines, which he didn’t understand. All the time, the girl was becoming stronger, and if, on occasion, he questioned Dr Kay’s methods, or what she chose to say and to withhold, she pointed to this. ‘Each day,’ she said, ‘Girl A progresses. She’s moving further and further away from that house – faster than any of the others. You see that, don’t you?’

‘Of course.’

‘Well, then. Let me do my work.’

When the interviews were over and the evidence collected, he was assigned to other cases, although he asked about the children often, and he continued to supervise the Gracie case. One evening, Dr Kay visited him late, as he was finishing work. The last pale spring light was sliding from the blinds. He was packing his bag and thinking of his bed, the smell of it and the sheets worn just the way he liked. He thought, too, of the beds at Moor Woods Road.

Dr Kay was waiting on a cheap plastic chair, every part of her out of place: the softness of her sweater, the cat-eye glasses, her hands on her lap, with the nails painted by somebody else. ‘Hello, Greg,’ she said, and stood to embrace him.

‘Coffee?’ he asked, and she nodded, although they each knew that she wouldn’t drink it. He took her backstage, to one of the interview rooms. The chairs had been abandoned at strange angles to the table, as though people had departed in a hurry. ‘Make yourself comfortable,’ he said. At the coffee machine, he found that he was frightened. He hadn’t expected to see Kay until Deborah Gracie’s trial. He took the coffee before the machine had finished, and it spat hot water at his hand.