I said, ‘Another few days of this and I will be.’ We laughed harder. ‘That’s one reason I’m out here. I needed a chat and a laugh with people who won’t have my head melted.’

They liked that. Arched like cats, gratified. Orla – she bounced back fast; used to getting hit – she said, ‘We decided you’re a way better detective than her.’

‘Lickarse,’ said Gemma.

‘It’s true, though,’ said Joanne. Eyes on me. ‘Someone should tell your boss that Whatshername being such a B means she can’t actually do her job. She’d get a lot further if she had some basic manners. When she asks a question, it’s like, whoa, anyone got a lump of raw meat to throw, and maybe it’ll back off?’

Orla said, ‘We wouldn’t tell her the time unless we had to.’

‘When you ask us stuff,’ Joanne said, and twisted her head to one side to smile at me, ‘we want to talk to you.’

Last time I talked to her, we hadn’t been best buds, not like this. They wanted something from me, wanted to give me something, I couldn’t tell which. I said, sniffing my way, ‘Glad to hear it. You’ve been a lot of help to me so far; I don’t know what I’d’ve done without you.’

‘We like helping you.’

‘We’d be your spies any day.’

‘Undercover.’

‘We’ve got your phone number. We could text you anything suspicious we see.’

I said, ‘If you seriously want to give me a hand, you know how. You three, I’d say you know everything that happens in this school. Anything that could have to do with Chris, I’d only love to hear it.’

Orla hunching forward, glint of moonlight on her wet mouth: ‘Who’s in the art room?’

A zap of ‘Shhh!’ from Joanne. Orla shrank back.

Gemma, amused: ‘Oops. Too late.’ To me: ‘We weren’t going to just ask like that.’

‘But since Genius here did,’ said Joanne. Leaned back, throat arching. Pointed. ‘Who’s that?’

The art room, a flare of chilly white across the heavy slab of the school. Above it the stone balustrade was silhouetted against the sky, a ghost’s walk, black on near-black. In one window the wire school soared. In the next one was Mackey, slouching back, arms folded.

‘That,’ Joanne said.

I said, ‘Another detective.’

‘Ooo.’ Wrist-shake, mocking eyes. ‘I knew you’d got thrown out.’

‘Sometimes we change things up while we’re working. Keep everyone fresh.’

‘Who’re they talking to?’

‘Is it Holly Mackey?’

‘We told you they were weird.’

The glow on their faces, all eager and fascinated. Like I could be the one thing they’d been hoping to see. It made you want to be that, everything they were looking for, all at the same time. Chris Harper must have wanted the same thing.