Round the next corner, the mirrors turn us into tiny boxes of humanity, and then into narrow discs. ‘It’s OK to get angry with someone. It doesn’t mean you love them any less. I love my parents to bits, but I can still see that my dad’s nerdy. And my mum gossips about people, which isn’t the best quality.’

‘I’d give anything for a family like yours,’ Casey says quietly.

And I want to say to her: Yes, yes, you’d be made so welcome. But I don’t want to give her false hope that anything might happen after today. Maybe I’ve already let her get too close.

The final mirror merges the two of us into one, and I link arms with her as we step out of the hall, back into the sunshine.

‘Where next?’ I ask as we scan the attractions: the ghost train, the helter-skelter. I notice her eyes widen as she sees something and follow her gaze: FORTUNES TOLD: PALM, TAROT, CRYSTAL BALL.

‘I’ve always wanted to have my cards read.’

Casey does not need some fake mystic giving her even more reasons to be worried about the future. ‘You know it’s not real, don’t you? Plus, it won’t be included in the wristband.’

‘Obviously no one can tell the future,’ she says, but she sounds so dejected that I wonder if a fortune teller might cheer her up with some vague chat about tall, handsome strangers.

‘Let’s talk to your dad and see how much they charge. But if you go, you must promise to take it no more seriously than the spooks on the ghost train.’

Dan seems as doubtful as me, but my mum’s on the case now. She knows Mystic Debs – apparently she’s a regular at the surgery because of her tennis elbow, and as a thank-you to the doctors, she did a turn telling everyone’s fortunes at last year’s Christmas party.

‘It was a riot, and there’s no way she’d say anything upsetting. Go on, Casey, my treat.’

While Casey has her reading, I fetch ice creams for everyone. Casey comes out smiling, but refuses to reveal what Debs said. We go down onto the shore, where Mel and Charlotte have been waiting with Bear. He tears across the sand as soon as he sees me, and it’s almost enough to make me forget this is the same stretch where Andrew and I posed for our last official wedding photo, as the sky turned crimson and the silvery sand rippled like fish scales beneath our bare feet. When I close my eyes, I almost feel the weight of damp silk around my ankles.

So don’t close your eyes.

I open them. Casey, Bear and Dan are chasing each other up and down the beach and I can hear laughter and barking. They’re not thinking about the past, so why am I?

The scene is so perfect I have to take a photo. I WhatsApp it to Dan, and then zoom in on Casey. She has colour in her cheeks, and there’s no hint of the nervy girl I first saw in the classroom at the hospital, flinching when she saw Bear.