‘There was a fire escape at the end of the corridor. There was a staircase the other side of the door. We weren’t allowed to go there, but I knew that’s where she was. The door was open, but before I could follow her, my mother found me and took me back to my room. The next day, she convinced me I’d been sleepwalking and had imagined the whole thing. But I never forgot it, Dee. And then, when I saw that woman on the Tube, it all came back to me and I haven’t been able to think about anything else since.’

‘Okay.’ Dee drank some wine while she tried to work out the best thing to say. ‘Tell me about the woman. Did you speak to her?’

‘I didn’t get a chance. She was getting off the Tube when I saw her. I ran after her, tried to call her back, but she didn’t stop.’

‘It must have been an awful shock,’ Dee said, ‘after all this time. But Emer, it’s not uncommon to see someone who reminds you of another person.’

‘I know that,’ Emer said. ‘And I know there’s every chance I got it wrong. But I need to make sure. What if I wasn’t dreaming that night? What if Kitty’s still alive?’

Dee didn’t bother pointing out all the reasons that was impossible. Like how unlikely it was that an eleven-year-old child could fake a drowning and disappear all by herself.

‘You’re a journalist,’ Emer said. ‘You’ve got experience investigating things, trying to find the truth. If Kitty really is out there, I can’t think of anyone better placed to find her.’

‘Well, I’m flattered you’ve got so much trust in me,’ Dee said. ‘But even I can’t work miracles. Finding a woman you saw once on the Underground? I wouldn’t know where to start.’

‘There’s more,’ Emer said. ‘I followed her when she left the station.’

Dee drank some more wine.

‘Keep talking. I’m listening.’

‘Outside the station, she got into a cab before I could catch her. So I did that classic thing you see in films. I jumped into the next cab that came along and followed her. She didn’t go far. A few minutes later, her cab pulled up outside a pub and she went inside. But by the time I’d paid my own cab driver and gone into the pub, there was no sign of her.’

‘So you made a mistake,’ Dee said.

‘Or she knew I was following her and she was hiding from me. I asked the barman if he’d seen her but he told me no one matching that description had come into the pub. He was lying.’

The poor girl was delusional, Dee thought. She needed counselling, not a journalist.

‘You checked the toilets?’