She’s right. Not everything she says is a lie. The story of Aidan and Martha, right up until the point where she hanged herself, that was all true. Except . . . yes, even the part about Mary writing to Aidan, berating him for treating Martha badly. Not literally true, but symbolically accurate, as accurate as she could be without revealing her true identity. There are divisions within every person. Especially those who are forced to bear unbearable pain. The Mary who wrote angry, accusatory letters to Aidan—though she wasn’t called Mary then—was the intelligent part of Martha Wyers, the part that could see the truth: that the relationship was going nowhere, that Aidan didn’t love Martha the way she loved him.

No surprise that he didn’t. Hard to love a woman who proclaims undying love one minute then savages you the next.

‘Tell me the story you think you know about me,’ says Mary. She sits down beside me and draws her legs up to her chest, balancing the gun on her knees. If I could move my right arm, I could grab it.

I worked it out, put it all together in the taxi on the way back here. I have to do it again now, force my brain to keep going. ‘Phone an ambulance,’ I say. ‘You can’t let us die.’

‘Aidan’s been dead for a while,’ she says matter-of-factly.

‘No,’ I moan. ‘Please. It might not be too late.’ Martha came back to life. Aidan can’t be dead. I won’t believe it.

‘Look at us. One bleeding body, one corpse, and a husk who’s been half dead for years. No one who took an objective look at this room could think it was anything but too late, Ruth. For all of us.’ She twists her hair into a spiral.

‘Private detective,’ I whisper. ‘Told you . . . Aidan’s stepfather . . . in prison for killing Mary Trelease. You’d seen the painting . . .’ No. Can’t get it wrong, can’t waste words or breath. ‘You’d bought it—The Murder of Mary Trelease. Bought it and . . . destroyed it, like you did all of them.’

‘No.’ Mary’s voice is firm. ‘I’m an artist. I don’t destroy art.’

In my head, I see a picture of a man and a woman in a bed. Naked, or the woman is. The man’s hands round the woman’s neck. The man recognisable as Aidan, so that Mary—Martha—knew Len Smith wasn’t the killer.

‘Why did he kill her?’ I mouth the words, not sure if I’m making any sound at all. I feel deathly cold all over my body. Like ice.

‘He’d have told you if he wanted you to know.’ Mary smiles.

‘Martha. Wasn’t. Alone. Any. More,’ I exhale one word at a time. I can do it. I can get to the end. ‘An ally . . . another woman Aidan had . . . hurt. Mary Trelease.’