A lot of those old adoption societies have lost their records, he wrote soothingly. Maybe, he thought to himself, but not a Crown Court, surely. Hope hadn’t suddenly appeared on the earth, fully formed, at the age of two. A woman had given birth to her.

It’s as if I don’t really exist! I’m baffled!

You and me both, Jackson thought. Hope McMaster’s past was all echoes and shadows, like looking into a box of fog.

The dog was sound asleep in the rucksack on the floor. Either that or it was dead. Jackson gave it a gentle prod and the rucksack squirmed. He thought of the woman he had woken up next to. He didn’t usually have to check that his inamoratas were alive the morning after. He unfastened the rucksack and the dog opened one weary eye and looked at him with the resignation of a pessimistic hostage. ‘Sorry,’ Jackson said. ‘We’ll go for a walk after this.’

The sandwich was egg and watercress. Not Jackson’s favourite, although he was so hungry that it was beginning to look attractive. The bowl of pasta yesterday evening on the Headrow had provided an inadequate cushion for the alcohol and dissolution that had followed. The bacon roll from earlier had disappeared into the maw of his hangover. He heard a clock strike eleven. It sounded like a church clock, incongruous somehow in this area. It seemed he had been forgotten about.

Jackson gave up and wrote a note of the ‘I was here’ variety on the back of one of his cards. The card – Jackson Brodie – Private Investigator – was one of many he’d had made when he set up on his own several years ago. A print run of a thousand. Such optimism. He had probably handed out no more than a hundred of the things, usually because he forgot he had them.

He placed the card on top of the sandwich, where hopefully Linda Pallister would notice it. Yesterday’s egg and cress was in turn sitting on top of a photograph, almost entirely obscured by the sandwich’s triangular box. The photograph was jumping up and down shouting at him, asking to see the light of day. It almost leaped into his hands when he uncovered it. Unframed, dog-eared, an old snap. He hadn’t seen it before but he had definitely seen the subject recently. Snub nose, freckles, an old-fashioned caste to the plump features – the spit of Hope McMaster in the photograph taken on her arrival in New Zealand. On the top edge of the photograph there was the mark where a rusty paperclip had attached it to something.

The photograph from Linda Pallister’s desk had been taken on a beach. A British beach, judging by the way the child was bundled in outdoor clothes. Despite the fact that she looked freezing she had a big grin on her face. Her hair was worn in cock-eyed bunches. First thing you would do with an illicit child would be to cut that long hair, adopt a disguise with a new haircut. Spiky, urchin. New hair, new clothes, new name, new country.

He would have sworn on oath that he was holding in his hand a photograph of Hope McMaster. He turned it over. Nothing. No helpful name or date, unfortunately, nonetheless Jackson experienced a visceral feeling, something that he recognized from his days in law enforcement. It was the reaction of a dog to a bone, a detective to a great big fat clue. He didn’t know what the photograph meant, he just knew that it meant something tremendously important. He thought about the ethics of taking the photo for all of two seconds before placing it in his wallet. Photographic evidence, you never knew when you were going to need it.

Enthused by his discovery and working on the theory that one clue generally led to another, he started to rake through the debris of paperwork on Linda Pallister’s desk. Nothing. No references to Winfields or Costellos. He tried the drawers in the desk. More confusion and chaos. But there in the last drawer – it was always the last drawer, the last door, the last box – was another object trying to claw its way out of the darkness. ‘Eureka,’ Jackson murmured to himself.

It was a folder, an old manila one, and there on the front of it was a small rusty paperclip, just the same size as the after-image on the photograph of the girl with the cock-eyed bunches. Jackson, in an instinctive sleight of hand, slipped the folder inside his own neonpink plastic one. He felt like a spy who had just discovered a dossier of secrets. In the nick of time too, as Eleanor, she of the great legs and not so great face, finally put in a return appearance. He caught the look on her face, a mixture of distaste and confusion which eventually resolved into something more cryptic. Women usually needed to be acquainted with him a little longer before he saw that expression on their faces.

‘Oh,’ she said. ‘You’re still here. In fact, you’re in here.’

‘Ms Pallister hasn’t turned up,’ he said, spreading his arms wide, a conjuror demonstrating innocence, as if he might have been hiding Linda Pallister on his person. Eleanor frowned.

‘Have you actually seen her this morning?’ Jackson queried mildly.

Eleanor’s frown grew deeper. She had the sort of face that should be kept in neutral. ‘I don’t know,’ she said.

‘Maybe she’s ill,’ Jackson suggested. ‘Maybe it was the sandwich she didn’t eat.’

The frown developed into something threatening. Jackson left before he was turned to stone.

He retreated to the nearest café, a little Italian place where he wasn’t disappointed in his assumption that they would know how to make coffee. He took a corner table and over a double espresso examined his stolen trophies.

The thin card of the manila folder was soft and felted with age. This was what folders used to be like before they became pink neon plastic. He had dealt with enough of them in his time. Of course, even the pink neon was an anachronism now in the days of the paperless office. Not something Linda Pallister had heard of, he thought, remembering the Dickensian piles of papers and files in her messy office. You could hide a small child – or a dog – in there and not notice it for days.

He opened the folder expecting to find something surprising – a clue, a secret, even a piece of bureaucratic tedium – but the surprise was that there was nothing at all. Jackson turned the manila folder upside down and shook it, just to be sure.

Nonetheless, despite being empty, the worn beige folder did have something it wanted to say. There was a small typed label affixed to the top left-hand corner. No one used typewriters any more, it was like seeing a message from a primitive culture, a lost time. ‘Carol Braithwaite,’ Jackson read. ‘Case worker: Linda Pallister’ and a date, 2 February 1975. Linda Pallister must have been very young at the time. Jackson would have been fifteen in 1975, a year older than his daughter was now. Getting up to no good, bunking off school, petty thieving, minor vandalism, sinking the good ship Woolworths. It was a long time ago.

And across the front of the folder was written the name ‘WPC Tracy Waterhouse’ again, this one in faded black biro, and another date, 10 April 1975. There was a phone number too, dating from before the national codes were changed. The year was the same year that Hope McMaster was adopted. April was the month that was on her adoption certificate, the one that didn’t exist officially. She had scanned it and emailed it to him, along with her birth certificate, which also didn’t exist officially. If they were forgeries they looked pretty genuine, although he supposed a scan wasn’t the best way of telling. His own forgery of a wife had been in possession of a pretty genuine-looking birth certificate, not such a hard thing to create.

In her appointments diary, Linda Pallister had written, ‘Phone Tracy Waterhouse,’ and here was Tracy Waterhouse’s name thirty-five years ago. Jackson took the photograph out of his wallet and looked at the stocky, wholesome little girl, with cock-eyed bunches. As he always knew it would, the paperclip on the folder fitted exactly over the rusted impression on the photograph.