She passes us, her eyes focused on something in the middle distance, but when she gets to whatever rock is her marker, she jogs back and kisses both children.

‘Yuk,’ says Lotte, wiping her cheek. ‘You’re all wet, Auntie Bee.’

‘This is excruciating,’ she says to me. ‘I feel like I’m waiting to have my molars pulled out.’

I don’t suppose she’s talking about running.

‘I’ve got some special presents for you,’ she tells Lotte and Theo. ‘I’ll give them to you when you get back from the beach.’

They nod solemnly, accepting presents as their right, since we’re going to have a party. Bethany is about to dart off again. I put out my hand to stop her.

‘Listen, Bee, do you remember when you took Dad for that memory test?’

She frowns. ‘Sometime last year.’

‘But when?’ I persist. ‘Was it before or after the funeral?’

‘I can’t remember. After, I think. Amy was barely speaking to anyone. I thought it might help her understand what had happened. Why?’

She does a calf stretch and knots her hands behind her back; the muscles in her shoulders pop. She’s wearing sunglasses, so I can’t see her eyes.

I shrug. ‘No reason. Just Dad couldn’t remember when he went.’ Only a small lie. I don’t want to tell her I’ve read his diary.

‘That’s no surprise, is it?’ she says.

I scuff the ground with my toe; the children, who’ve grown bored, start to drift down the hill towards the beach. That’s true. Or it might be true.

‘I was going to make a follow-up appointment. It’s been a year. He could have got worse.’

‘He probably has. I’ll do it when I get home,’ she says.

We both glance towards the kids, but they’re fine – they’ve almost reached the sandy bay.

‘I can go with him. I’ve got more time than you.’

‘To be fair,’ she says, swapping legs and stretching the other calf, ‘I know a lot more about dementia than you, so it’s best if I take him.’

‘Okay. Where?’

‘Back to the hospital, where I took him before,’ she says, like I’m an idiot.

I nod and shout, ‘Wait up!’ before jogging to catch up with the children.

Am I being an idiot? Why would my sisters lie about what my father was drinking, or about Bee taking him for a check-up at the hospital? It’s much more likely that my father really is suffering from dementia. After all, he has been forgetful since we got here.

And the only reason – absolutely the only reason for Bethany to lie – is unthinkable: that she didn’t ask Dad to look after Ruby-May one year ago today. Literally unthinkable.