Her lips tensed up and she bit down hard, trying not to cry. ‘She was happy to meet you. She went out to sell another clock, then was going to join you after.’ Her hair loose, and Mutti’s comb holding it in place. ‘We needed the money, from the clock. From your lessons.’ Betty hadn’t told a soul this, not to her father, not to Dee. ‘You see, she was pregnant.’

And so am I.

His eyes were moist when he turned to her. ‘Oh my God.’ He raised his hands, palms facing out. ‘The baby wasn’t mine. I swear.’

Of course it wasn’t his, she knew that. She didn’t want to hear his denials, his excuses.

‘And then what?’ she said. ‘What happened then?’

‘I can’t tell you what happened after.’

‘Why not?’

He took a deep breath. She knew he wasn’t going to answer. This was her sister. Did he enjoy this mystery? This cloak-and-dagger war? Was he doing it to hurt her?

‘It’s all top secret, that’s why, to do with my job, in the war. I said that earlier. They wanted information, that’s all I can say.’

‘Who’s “they”?’

‘The Russians.’

‘What information?’

‘I can’t tell you that either.’

‘You can’t tell me anything,’ she said, fury and exasperation bubbling. Her head tensed and she felt dizzy. ‘You could be making this up. For all I know, you could have killed her and blamed it on the Russians. How convenient.’

‘Please, Betty,’ he said. ‘You must believe me.’

‘And now?’ she said. ‘What’s this got to do with now?’

‘One of the Russians I met that day is in London, and has made contact with me.’

‘Why?’

He wet his lip, fiddled with the packet of cigarettes in front of him. He took one out, lit it. The ashtray was brimming over with butts.

‘They think I owe them. Can help them again.’

‘Do you? What with?’

‘Nothing,’ he said. ‘But I have to play them along.’

‘Who says?’

‘Please, Betty. I didn’t want to get you involved. I can’t tell you anything.’ Betty could hear the clang of a fire engine in the distance, and below in the street, the distinctive chug of a London cab. A cool breeze crept in through the half-open window, made her shudder. ‘Except that they have you in their sights.’

‘Me?’ She laughed. ‘You’re out of your mind. Why on earth would they want me?’ She watched as he sat down again, his mouth playing with silent words. ‘I can’t tell you,’ she said, mimicking his reply before he said it. He breathed in, and she saw the veins on his neck swell and pulse.

‘What I can tell you,’ he said, ‘is that you are their route to your father. What I can’t tell you is why.’

She could feel her guts tighten.