Tom was still looking at the picture on the laptop screen. ‘I know her,’ he said. ‘I know this woman.’ They turned to stare at him. ‘I met her when I was qualifying in Manchester, about – what? – ten years or so ago. Her name’s Hannah.’ He shook his head in confusion. ‘But I don’t understand. Why is she pretending to be my sister?’

‘How did you know her?’ Mac asked.

‘She answered an advert for a room in a house I shared. We gave the room to someone else, thank God, but after that she seemed to be everywhere. Wherever I went – supermarket, pub or gym or whatever – there’d she’d be. I’d turn around to find her staring at me. If I approached her, she’d just walk off. It was really fucking weird. Then suddenly, she disappeared. Vanished out of the blue and I never saw her again.’

Clara listened to him in amazement. ‘But who on earth is she? None of this makes any sense.’

At that moment they heard footsteps on the stairs, and Oliver and Rose, crumpled and dazed in their dressing gowns, came into the room. ‘What’s happening?’ Oliver asked. He started in surprise when he saw his son. ‘Tom? What are you doing here?’

Clara glanced at Tom, then said to Rose and Oliver. ‘Something very strange is going on.’

Rose put her hand to her mouth. ‘What?’ she said nervously. ‘What is it?’

‘I found this picture in the flat,’ she said, passing it to her. ‘I thought it might be someone who … well, anyway, I didn’t know who it was.’

Rose visibly flinched when she saw it. ‘Emily,’ she whispered, her face stricken.

Oliver came and stood behind her and the two of them looked down at their daughter’s face in silent anguish.

‘The thing is,’ Clara said, ‘after the TV appeal I was contacted by someone saying they were Emily.’

Their eyes shot to her face. ‘What?’ said Oliver faintly.

‘I met with her … and a while later I found this picture in Luke’s filing cabinet, not knowing that this was the real Emily.’

Rose and Oliver had gone very white. ‘What did she look like, this woman?’ Rose said, her voice little more than a whisper.

‘Here,’ Mac said. ‘I have a picture of her.’ He passed them his laptop and they stared down at it for a long time.

Rose began to shake uncontrollably. ‘Oh,’ she said. ‘Oh dear God, Oliver.’

‘Do you know who she is?’ Tom demanded.

After a silence Oliver said, ‘Yes. We know who she is.’

Rose’s voice was loud. ‘Oliver,’ she cried. ‘Don’t! Do you hear me? Don’t you dare!’