Harper waited while Gideon hastily removed the container in which there was something that resembled a bright green brain, to somewhere Harper did not have to see it, think about it, or arrest him for it. That amount of marijuana would put him away for a year or more, and right now Gideon was far more useful to Harper if he remained a free man. Though she was perfectly willing to reassess this opinion at any time, should the need arise.

“So, Amy my Amy, what’s up?” said Gideon, folding his thin frame into one of his huge armchairs. The couch on which Harper sat had once been blue, but the arms were now brown and tacky to the touch. She perched, unable to relax. Amy stood a short distance away.

“Well, Joanna and I, we’re having a little problem, and neither of us have the specific skills required to sort it out,” said Amy. “I immediately thought of you, but of course at the time I had no idea that you two had any history together.”

“It’s fine,” said Gideon, his eyes on Amy, “I don’t hold grudges.”

“I knew you’d say that,” said Amy. “I told her you were a good sort.” She turned to Harper. “Perhaps you can explain to Gideon what it’s about?”

“I have a CCTV tape, and an audio recording. I need someone with technical expertise to analyse them for me.”

“From a criminal case? Why don’t the police nerds look into it?”

“The boss doesn’t know I’m here. This is kind of a side project,” said Harper. “Off the books, so to speak. Can I really trust you not to tell anyone?”

“Sounds like exactly my kind of thing,” said Gideon, “a police officer coming to me with some secret bits of evidence they want me to take a look at, that the rest of them don’t know about. Of course I won’t tell anyone. This is what I live for, the mainstream going underground, undermining their own, seeking out what’s hidden. Ha. Show me.”

Gideon opened his laptop and pushed the flash drive that Harper handed him into the USB port. Very soon the screen opened on the maternity ward, the nurse intent on the keyboard, the picture green and slightly fuzzy.

“There,” said Harper, “those shadows. That’s what I’m interested in.”

“OK,” said Gideon, “what do you want to know?”

“Are they real—as in, did the camera capture them happening in the room, or are they a mistake, some sort of damage on the file?”

Gideon watched the section again. The three shadows swam across the floor at the corner of the screen. He zoomed in, played it again.

“It looks like it might be both.”

“What do you mean?”

“Look,” said Gideon, “see how the shadows follow each other? And just there,” he paused the tape, “you can make out the shape of a foot.”