Oliver looked up at his son imploringly. ‘If she was going to kill Luke she would have done so by now, not continued to send pictures and taunt us like this. She knows if she kills him there’s nothing to stop us going to the police. It wouldn’t be in her best interests; she wants us to suffer for as long as possible. It’s a game to her, that’s all. It’s our punishment.’

As Clara listened to Oliver talk, she remembered how frequently Hannah had enquired after her father and Rose’s wellbeing during their meetings, how avidly she listened when Clara described their suffering. Her desire to see Clara wasn’t just to keep abreast of the police search; it was an opportunity to revel in the havoc she had caused.

Rose got to her feet then and, approaching her son, put her hand on his arm. ‘Tom, you have to understand that Hannah has never given us a straight answer about Emily’s whereabouts. Sometimes she says she knows, other times she denies it. She might have some information, no matter how small, that could let us know what happened to her. If the police catch Hannah before us, she’ll never tell us. She would go to prison and keep quiet just to spite us. At least this way, if we do what she wants, there’s still a chance she could tell us something, anything, that might help us find Emily.’

‘Christ!’ Tom shook off his mother’s hand. ‘What the fuck are we going to do, then? How are we going to find Luke?’

There was silence, and then Clara said, ‘She doesn’t know that I know who she really is, yet. She thinks I still believe she’s Emily.’

Tom looked at her. ‘That’s true.’

‘So if I arranged to meet her again, one of us could follow her, to see where she goes.’

Mac shook his head. ‘It’s too risky, she knows what we all look like, even me, she’d spot us a mile away.’

‘Then who?’ said Tom.

The following morning, Tom, Mac and Clara sat in a café in Greenwich, nervously looking at the door. ‘Do you think she’s going to come?’ asked Mac.

Clara nodded. ‘She wouldn’t let me down.’

A moment later, a tall, auburn-haired woman with a baby strapped to her chest walked through the door.

It took nearly half an hour to bring Zoe up to speed. When they’d finished, she looked at them, speechless with shock. ‘Holy fuck,’ she said at last, shaking her head. She looked at Clara. ‘Why didn’t you tell me this was going on?’

Clara took hold of her hand. ‘I’m sorry. But will you do it? I wouldn’t ask if we weren’t absolutely desperate. We just need you to follow her as far as you can.’