But that approach had taken her nowhere. ‘You won’t succeed in sowing doubt in my mind, Miss Wada. I’m acting for the best. As you’ll appreciate yourself in the fullness of time.’

Quizzing him about Emergence had proved equally fruitless. ‘If I have to stay here until Thursday, you can surely tell me what is going to happen in the meantime.’

‘No, Miss Wada, I can’t. I’m not obliged to explain anything to you. Remember, I didn’t ask you to come here.’

‘In a sense, you did, by agreeing to meet me in London and then failing to turn up.’

‘I agreed to meet Mimori Takenaga, not you.’

‘So, you are saying it would be different if I really was Mimori Takenaga.’

He’d bridled at that. ‘No, I’m not saying that, dammit. You’re trying to bamboozle me, but it won’t work.’

She’d left it there. Angering him didn’t strike her as a good idea.

As to what might constitute a good idea …

The snow had evidently stopped. A slow thaw had set in. Wada could hear a steady drip-drip from the eaves, though she could see nothing of the outside world, because Caldwell had shuttered the bathroom window and refused to unshutter it. Eighteen hours into her captivity, she’d brought her fear and frustration under control and was now thinking, coolly and logically, about how to escape.

Caldwell, she reluctantly concluded, was the answer. He would have to be induced to set her free. He would have to be made to trust her.

She would have to make him trust her.

Nick decided to tell Erla everything because he could see she was genuinely frightened and only complete sincerity was going to persuade her to open up to him. He showed her pictures on his iPhone of his paintings and the paintings of some of his students. They seemed to convince her he really was the person he claimed to be. And then, of course, there was the famous Western Morning News photograph of Peter Ellery, Martin Caldwell, April Vyse, Caroline Miller and Alison Parker waving their protest banners by the Redruth to Portreath road on Easter Saturday, 1977. Erla recognized Caldwell. And she recognized Nick in his father’s younger self. She recognized the truth.

It wasn’t long before she was telling him the truth from her side as well. She wanted to confide in someone. She needed help and advice. She needed to know what to do.

She’d heard nothing from Umiko Wada since one brief phone call on Sunday night, reporting that the raid on Quartizon’s offices had gone wrong and Kristjan had been arrested, but she’d got away – with something. What that something was she hadn’t said.