‘Very perceptive of you, Miss Wada. Yes, of course, it was as much as anything about Alison that I wanted to know. She was the centre of my thoughts. Only Peter could tell me what had really happened to her. If he was alive.’

‘Why do you think Caroline Miller sent you the advertisement?’

‘Because she knew I’d been torturing myself over what had happened for more than forty years and, with death approaching, felt she should do what she could to lighten my burden.’

‘You mean she thought you deserved to know the truth?’

‘Yes. That’s what it comes down to.’

‘And she was right to think that?’

Caldwell frowned at her. ‘Obviously. It was a truth that profoundly involved me. I had a stake in those events that I’d argue entitled me to a proper understanding of them.’

‘I agree. And … do you have a proper understanding of them now?’

He nodded solemnly. ‘Yes. I do. Peter has told me everything that occurred.’

‘Everything that occurred that night?’

He nodded again, a little impatiently this time. ‘Yes.’

‘And everything that occurred later that summer, between him and Shitaro Masafumi?’

‘He gave me the gist of that as well. Likewise the circumstances that led him into business partnership with Hiroji Nishizaki. But if you think I’m going to share any of those details with you, then I’m afraid you’re going to be disappointed. Matters are unfolding that I’m not free to speak of. They require discretion on my part – and inaction on yours. Hence the regrettable necessity of holding you here, Miss Wada.’

‘Actually, you may be interested to know that Miss Wada is not strictly the correct way to address me. I am a widow.’

‘Oh. Sorry. You should have mentioned it sooner.’

‘I did not quite know how to. It involves a strange coincidence. My husband was killed in the sarin gas attack on the Tokyo subway in 1995. You have heard of it?’

‘Yes. Of course.’ Caldwell looked genuinely sympathetic. ‘I’m very sorry to hear that.’ His expression grew cloudy. ‘Sarin again. Such a terrible thing.’

It might be more terrible than Caldwell knew, of course, since Yozo Sasada, the man who’d released the gas, had worked for Quartizon. But now wasn’t the moment to allege a connection between Quartizon and the Aum Shinrikyo cult. Now was the moment to capitalize on the sympathy she’d just generated. ‘This handcuff is beginning to chafe my wrist, Mr Caldwell.’ She raised her arm so he could see the rash the ring had caused on her flesh. ‘It will only get worse, I fear.’

‘There’s nothing I can do about that, I’m afraid.’

‘You can release me.’

He sighed. ‘As I’ve already explained, I can’t trust you not to go back to Reykjavík and try to interfere in Peter’s plans.’