‘Gemma told you about my name? Was she very upset? She must hate me.’

‘Why do you care?’ Angelica is crying again now and, despite everything, I want to comfort her and, more than anything, I need to find Casey.

‘We can talk about this later. After we find Casey.’ There’s silence at the other end. ‘Angelica?’

She sobs. ‘What if we don’t find her?’

For the first time, that possibility fills my head, more appalling than the most deafening burst of tinnitus.

My city no longer seems like a friendly place. Instead the floodwater and the cobbles and the cyclists and the cars and the strangers – all the strangers – loom like threats, a million hazards that could take Casey from us.

‘We are going to find her.’

I wait for Angelica to challenge me, because neither of us can know for sure.

‘Yes. You’re right. She’s going to be OK. Call me once you’re on the road,’ she says.

I get hold of Vijay as I’m walking into the underground car park.

‘Hi, Dan, what gives?’ He sounds as cheerful as ever.

‘Veej, I need your help. Harrison’s help.’

‘O-kay.’ I can hear the question in his voice.

‘It’s Casey. She’s . . . gone.’ My voice cracks on the word.

‘Gone where?’

‘We’ve no idea. She left the hospital on her own, two hours ago now. Isn’t answering her phone. And it’s my fault. Why didn’t I tell her the truth sooner?’

‘Because you’re a human being. Listen to me, Dan, what’s done is done. You need to stay calm and focus on finding her. What can I do?’

I load my stuff into the back, peel off my sopping raincoat. ‘Is Harrison there? He might have heard from her. Or have some ideas of where Casey could have gone?’

‘He’s out with friends. I’ll see if I can get hold of him.’

‘He wouldn’t be with Casey, would he?’ Hope makes my heart beat even faster.

‘Didn’t say so. I’ll track him down and call you as soon as I have. She’s a smart cookie, Dan, she’ll be somewhere sulking, and hoping you’re all suffering. It’s what they do sometimes. To prove to themselves how much you love them.’

‘I hope you’re right. I don’t think I’d even realized till now how much I did.’

Vijay sighs. ‘Mate. I hear you. Call me when you’ve got any news.’

I drive and I drive. St Nick’s Market, the road next to BayCaff – everywhere I can think of. I leave the jeep on double yellows to dart into the spaces I can only explore on foot. When I return the third time, there’s a warden writing out a ticket. I show him the photo of Casey I took on the beach and beg him to keep an eye out. Soon he’s cancelling the ticket and posting her picture in the Bristol wardens’ WhatsApp group.

WhatsApp. I should check when Casey was last online.

She hasn’t been on the app since nine this morning. I can picture her around that time, going into the proton beam room alone – facing every new treatment with courage that awes me.