‘It was so stupid,’ she mutters, opening the bottle again and topping up her glass.

I get the impression she wants me to ask her what it was about but when I do, she snaps, ‘I just told you it wasn’t important.’ She glares at me as if goading a reaction, but I just shrug. ‘What did they ask you anyway?’ she says, and almost scornfully adds, ‘You didn’t even know her that well.’

‘That’s what I told them. All I could say was what little I did know.’

‘Which was?’

‘The basics. That she was over as part of her university degree—’

Bonnie laughs suddenly and then says, more quietly, ‘That wasn’t even true.’

‘What do you mean?’

‘She didn’t go to university.’ She studies me carefully, looking pleased that she’s caught me out, but as I stare back at her, incredulous, her expression changes. ‘She just said she did,’ she adds.

‘But …’ My eyes follow Bonnie as she pulls herself off the sofa. ‘I don’t understand. What did she come to the island for, then?’

She shrugs and says, ‘She liked to tell stories. That was just one of them. Anyway, I need the toilet.’

‘Bon,’ I call as she disappears. I wait for her to come back and when she does she asks me if I’ve spoken to Dad. I shake my head, refusing to let her determine the conversation. ‘You didn’t answer my question. Why did she come to the island if it wasn’t for part of a course?’

Bonnie drops on to the sofa, hunching her body stiffly as she stares out of the patio doors. ‘I don’t have a clue why she came.’

Sometimes when people are lying they change positions quickly. Nerves make people fidget. I have learnt to spot the ones whose heads suddenly turn in a different direction. But I also notice the ones who don’t move at all. It means they are preparing themselves for confrontation. And as Bonnie is immobile, my guess is she knows exactly why Iona came to Evergreen.

But maybe it’s not relevant, I think, knowing better than anyone that pushing her will get me nowhere. It’s been a long day, and as I haven’t been home for the last two nights, I tell her I need to go after half an hour. I’m passing the living room when Luke shoots off the sofa and follows me to the door. ‘I’m going to the shop,’ he tells Bonnie, jangling his car keys in one hand. I kiss my sister on the cheek and say I’ll call in the morning, then follow Luke out of the house.

‘What’s happening with you both?’ I ask as we walk to the end of their drive.