Nella’s room, the room I’d used on Saturday night: I knocked gently.

Nothing. I crept through, past the unmade bed, into her bathroom. Took a breath, opened the glass-fronted cupboard above the bath – full of make-up, face cream, body lotion.

No drugs.

I ran my finger along it, but the windowsill was clear of the white powder I’d racked out on Saturday night. Shame.

I nearly opened the window to see what Fin might have been looking at – but I was pushed for time already.

Instead, I pulled open the more obvious candidate: the arty metal cabinet above the basin. This was more like it: bursting with pills and potions.

Zolpidem, the first bottle I pulled out. Prescription only but there was no pharmacist’s label. I slid them into the pocket of my harem pants. Amazing what money could buy.

‘What are you doing?’

Willow, behind me in the doorway: the alley cat, legs stiff with fury, back arched. I should have locked the door.

‘Ah. Miss Jackson, I presume,’ I said calmly – and, indeed, I felt calm. ‘I’m just looking for a magic pill.’ I turned back to the cupboard and picked up a few bottles to read the labels. Diazepam. I itched to pocket them too.

‘What do you mean “a magic pill”? And why are you looking here?’

‘Why not?’ Another bottle: diet pills.

She shrugged. ‘You’re a junkie, I guess.’

‘Half right,’ I agreed, feeling slightly less calm. ‘But it’s not for me.’

‘Oh?’

‘Your little brother told Ruby you’d given Zach something that made him sick. I was wondering about Rohypnol.’

‘Rohyp – what?’

‘But I think this is probably more your style.’ I showed her the bottle of Xanax I’d just plucked from the cabinet. Nella’s prescription, according to the side. ‘Strong stuff. Only private doctors prescribe this in England. But I expect you know all about Xanax.’

‘What’s Xanax?’ She watched me through narrowed eyes.

‘I think you’ve got a pretty good idea, haven’t you?’ I held the bottle up, just out of her reach. ‘Is this what you gave Zach last Saturday?’

‘Who said I gave him anything?’ She hardly missed a beat, but I saw doubt flare in her face.

‘Your brother told Ruby. Very factual, isn’t he? But what I don’t get is why?’

‘Why what?’ Willow shook her head. With her hair drawn back in a sleek ponytail, in her uniform, wearing no make-up herself, she looked every bit the innocent schoolgirl – around her real age, for once.

But she was not innocent, I reminded myself. Not fully.

‘Tell me, Willow, what have you got against Zach? What did he ever do to you?’

‘Nothing.’ She shrugged again. ‘I couldn’t care less about him. Or his stupid, tarty mum.’

‘Wow.’ I hadn’t seen that coming. ‘That’s not what I’d ever call Ruby.’

‘She is a tart.’ She scowled. ‘She tried it on with my dad.’

‘Really?’ I watched her closely. ‘Are you sure about that, hon?’