‘And you’d like to talk about that here?’

‘I wondered whether other people felt the same. And why it happens. I mean, if I cut my finger on a piece of paper or whatever, it hurts like hell. So why do I like it when I do it to myself?’

‘That’s a really good question.’ Dr Sharp nods, then scans the room. ‘Does anyone else feel like Molly?’

‘I know why she enjoys it,’ another girl mutters. Tasha, Katherine remembers. She’s only 14 and this is her third stay in a residential unit, so she gets a bit of kudos for that. ‘My therapist on the outside explained it once.’

‘Thanks, Natasha. Do you feel comfortable sharing your therapist’s explanation with the group?’

Tasha shrugs, looks down at the laminate floorboards. ‘It’s to do with your brain,’ she says. ‘There are two parts – I can’t remember what they’re called – that process your pain. And that’s both emotional and physical pain. When you’re feeling really shit, if you cut yourself, you reach peak sore. But physical pain always subsides somehow, and it takes the emotional pain with it.’ She slides her socked foot along the floor and the shushing sound is louder than Katherine would have expected. ‘It doesn’t last long, but you know, whatever.’

‘That’s exactly right, Natasha,’ Dr Sharp coos. ‘And thank you for also pointing out that the relief is short-lived. Our job here is to come up with ways to reduce the emotional pain in a less destructive, and longer-term, way. Does anyone have any ideas on how we might do that?’

Silence follows for a while, every girl hoping someone else will fill it. But eventually one of them surrenders. Katherine can’t remember her name. ‘Talking?’ The girl says it as a question, as though Dr Sharp might disagree with her. Which she never ever does.

‘Absolutely, Emma. Talking through problems is fundamental to recovery.’

‘Writing things down?’

‘Journalling is another excellent way of processing negative feelings, Amira.’ Dr Sharp smiles at the dark-haired girl, then widens her gaze to take in the whole group. When she zeros in, Katherine knows what’s coming. Three, two, one … ‘Katherine, do you have any ideas on how to lessen any emotional pain you might be feeling?’

Of course she does. Travel back in time and not go to that assembly, or not storm out of her house on her birthday. Not meet Becca at all. But would she really want that? To miss out on what they had even though it ended so badly? Because the images are still vivid in her mind. Becca’s beautiful face and perfect skin, her kind eyes and wide smile, her protective hand on Katherine’s arm. But there are the other images too now. The way her body fell and crumpled. All that blood.