Claire Draisey’s manner was brisk, impatient. ‘This has to be the last time, Mary,’ she said. She was wearing a red dressing-gown and slippers, and looked exhausted. I’d warned Mary that everyone at the school might be asleep, but she’d dismissed my concern. ‘They get woken up all the time,’ she said. ‘It’s a boarding school—goes with the territory. The staff who are soft enough to need to rest don’t live on site. In exchange for their beauty sleep, they’re frowned upon and overlooked for promotion. ’

Strangest of all was what Claire Draisey didn’t say: she didn’t ask Mary what or who she was worried about, why she wanted the police to check the house. The policeman who was there didn’t ask either. He and Draisey had a familiar manner around one another, as though they’d done this many times before. He checked that all the doors and windows were secure. He and Mary went into the cottage together and checked for intruders. Mary asked him if he’d wait outside in his car until it was light, but Claire Draisey said, ‘Don’t be silly, Mary. Of course he can’t.’

‘This time there’s been an actual threat,’ Mary told her. ‘It’s not only myself I’m worried about.’ She indicated me. It made me feel flustered. So does the breakfast and tea on a tray. I don’t want to like Mary, not after what she did to me at Saul’s gallery. If she can attack me and still be a good person, what does that say about me?

What does it say about Stephen Elton and Gemma Crowther?

‘I can say their names,’ I tell her as she puts the sandwich into my hands. ‘The people who lived at Cherub Cottage. I’ve called them Him and Her for years. I couldn’t write their names when I wrote you the letter. But now that you know the story, I can say them. He was called Stephen Elton. She was called Gemma Crowther.’

‘Was?’

‘Is.’

Mary nods. ‘I know.’

‘What?’ The air around me thins out. I feel dizzy, as if I’ve been deprived of oxygen.

‘There’s a lot I need to tell you.’

‘You can’t know their names. It’s not possible.’

‘You’d better sit down,’ she says, bending to pick something up. The sandwich. I didn’t realise I’d dropped it. I stay on my feet.