I turn round and look up at Bethany’s flat. She’s standing in the window, watching me. I can barely see her face, she’s haloed by the brilliance of the studio lights. I slide my phone into my pocket and I wait for my sister.

She walks across the cobbles towards me. The bruise and the scar are livid, where the make-up artist has let them shine through her foundation. She moves carefully, as if she is trying not to jar anything. We stand there for a moment, facing each other. Although the sun is warm on my back, there’s a chill wind rising from the water and I shiver. I wonder if it’ll rain again. It rains practically every day in Bristol. And I realize that I knew – I knew all along it was Bethany. The sadness is almost unbearable. My own sister.

‘Luca,’ I say.

‘How did you know?’

I hold out my hand. The piece of plastic I found on the beach lies on my palm. It’s a tiny black pawn from a travelling chess set.

‘I found it on the beach next to a rock covered in your blood. I didn’t realize what it was at first, and then I thought it was a coincidence. But it’s not, is it?’

She squeezes her eyes shut and winces. I wonder if there is a blood clot, swelling inside her brain, pressing against her skull. How long she has to live. If she’s about to die.

‘Luca wanted you to admit it. Apologize. He went a little far – he’s not naturally a violent man, is he? He didn’t mean it to go so badly wrong. But when you cracked your skull open… well, he didn’t think anyone would find out it was him, once you were dead. And then you came round and he was in the clear! He hadn’t committed murder, and he thought the attack would be blamed on a random drunk, or your own inebriation, because there’s no way you’d tell anyone it was him. If you did, you’d have to say why a mild, gentle student, a man studying to be a child psychologist no less, would want to kill you. It was a relief, really, when Matt told the police you were probably drunk – so you confirmed it. They dropped the case. Problem solved.’

‘I loved her. I loved her! Don’t you understand?’ Bethany says.

‘I do,’ I say. ‘Just not enough.’

She takes a deep, jagged breath. ‘If I’d told Amy, it would have destroyed my relationship with her. How could she ever have spoken to me again, if she’d known it was my fault? I’d never have seen Lotte and Theo or Chloe. You and Dad. Think of our family, Nick, of what this will do to them.’