‘I saw them together. After she was supposed to have left the island.’ I turn to my sister. ‘I know Dad lied about taking her back, or at least about not seeing her again.’

‘What were they doing?’ she asks hesitantly.

‘Kissing.’

‘No! No. That’s totally not true.’ Bonnie snorts though she’s staring at me as if she isn’t sure any more. As if something else is dawning on her. ‘That’s totally sick. I mean, God …’

‘She never said anything to you?’

‘That she was seeing my father?’ Bonnie laughs but her face has paled. ‘Of course not,’ she mutters. ‘But I knew she was seeing someone. She’d just never tell me who.’

‘Dad says he wasn’t. When I saw him yesterday he seemed totally convincing. Only …’ I pause, shuddering. ‘Bonnie, the place I saw them was the spot Danny says he killed her.’

‘Oh my God!’ Bonnie cries. ‘This is getting even more horrendous. You have to stop.’ She falls into her hands as they clutch her head, her fingers digging into her scalp. ‘Just stop talking about it now. I wish I’d never come.’

I sit on the bed beside her again and for a while neither of us speak.

‘I never stopped wondering if what Iona said was true,’ Bonnie eventually says in a whisper. ‘But I decided I never wanted to know. And I don’t. I just can’t – I can’t even go there.’ She looks at me imploringly. She needs me to drop what I’m searching for. I can’t keep unearthing our past, because for Bonnie that’s where it needs to stay.

She isn’t like me. Or my client who admitted she would have begged for the truth regardless of its outcome. I was wrong to think everyone would. For my sister, it’s easier to accept that what she doesn’t know won’t hurt her.

I wave a hand in the air. ‘Iona must have got the wrong person. There’s no way Mum and Dad were capable of kidnapping a child,’ I say, though my thumping pulse reminds me I don’t know what to believe any longer.

‘I don’t want to know, Stella,’ Bonnie says again.

She glances at the bed. ‘I’ll sleep here. We’ll both go home in the morning.’

‘Yes.’

‘Promise me, Stella.’

‘We will,’ I say.

‘I want you to promise.’

‘I promise,’ I tell her.

‘It’s sad, isn’t it?’ I say when we are lying together in bed. It’s the first time we’ve done this since right after Danny left when I’d turned up on her doorstep. Only this time it’s my arms that are wrapped around Bonnie. ‘That we never felt we could tell each other the secrets that have been eating away at us for so long.’

Bonnie nods but doesn’t answer.