She improvised a story about contacting Caldwell on the internet as a result of their shared interest in the history of sarin production, hers based on the death of her husband in the 1995 Tokyo subway attack, his on personal knowledge which he’d promised to impart when they met. As far as she could tell, the policeman swallowed this story whole. But, then, why wouldn’t he? Wada could play the winsome innocent when she had to and the gash on her forehead only made that easier. He ended up apologizing to her for being attacked in such a normally peaceful neighbourhood, which she thought was, ironically, very Japanese of him.

The doctor who examined her at the hospital diagnosed concussion, which explained her dizziness and the strange sensation whenever she moved that her brain was lagging a fraction of a second behind her body. She was given an MRI scan, her wound was dressed, painkillers were prescribed and she was told she’d be kept in overnight for observation. By the morning, the police might have more questions for her, but the doctor saw no reason, barring a sudden deterioration in her condition, why she shouldn’t be discharged at that point.

The Stapletons’ outrage at her abuse of their hospitality had given way to sympathy. She was a stranger in a strange land; she’d lost her husband in awful circumstances; she’d meant no harm by taking the key: what had happened wasn’t her fault. They assured her they’d encourage the police to go gently on her. And if there was anything they could do to help when she left hospital …

‘That’s too kind of you,’ she told them. And, really, she knew it was too kind. She’d lied to them. And she was still lying. Sadly, she didn’t see any way she could tell them – far less the police – the truth. That, after all, would require her to mention the facetrail memory stick which could so easily have ended up in her attacker’s hands. Maybe it was that he’d principally been looking for. As it was, she had it. And she was keeping it. If there were clues to follow, she meant to be the one following them. She couldn’t trust anyone except herself to get the job done.

Lying in bed in a sparsely populated ward late that afternoon, she did her best between unpredictable bouts of sleep to plan her next move. To read what was on the stick, she needed her laptop, which she’d left in London. The phone number on Caldwell’s jotter pad was a different matter, however. Fishing her phone out of the bedside locker, she tried the number.

‘Hotel Arnarson.’ It was a man’s voice, speaking English with a non-English accent.

‘You are … a hotel?’ Wada asked in an undertone.

‘Pardon me?’

She raised her voice slightly. ‘You are … a hotel?’

‘Yes. Of course.’

‘Where … are you?’

‘Reykjavík.’