McKenna didn’t look at us. She got Alison’s shoulders and spun her, face to face. ‘Alison! Quiet!’

Alison swallowed a shriek, choked on it. Stared up at McKenna, gulping and red-faced. Swaying, like she was hanging from McKenna’s big hands.

‘Gemma Harding,’ McKenna said, not taking her eyes off Alison. ‘Tell me what happened.’

Gemma found her jaw. ‘Miss, we were just in our room, we weren’t doing anything—’

She sounded years younger, looked years younger, a shaken little girl. McKenna said, ‘I’m not interested in what you weren’t doing. Tell me exactly what happened.’

‘Alison just went to the loo, and then we heard her screaming out here. We all ran out. She was . . .’

Gemma’s eyes zipping around the others, finding Joanne, grabbing for signals. McKenna said, ‘Continue. At once.’

‘She was just – she was up against the wall and she was screaming. Miss, she said, she said she saw Chris Harper.’

Alison’s head fell back. She made a high whining noise. ‘Alison,’ McKenna said sharply. ‘You will look at me.’

‘She said he grabbed her arm. Miss, there’s – there’s marks on her arm. I swear to God.’

‘Alison. Show me your arm.’

Alison scrabbled at the sleeve of her hoodie, limp-fingered. Finally managed to pull it up to her elbow. Conway swept girls out of our way.

First it looked like a grip-mark, like someone had got hold of Alison and tried to drag her away. Bright red, wrapped around her forearm: four fingers, a palm, a thumb. Bigger than a girl’s hand.

Then we got in close.

Not a grip-mark. The red skin was puffy and bubbled, thick with tiny blisters. A scald, an acid burn, a poison weed.

The press of girls rippled, necks craning. Moaned.

McKenna said acidly, ‘Were any of you unaware that Alison suffers from allergies? Please, raise your hands.’

Stillness.

‘Did any of you somehow miss the incident last term when she required medical attention after borrowing the wrong brand of tanning product?’

Nothing.

‘No one?’

Girls looking at sleeves twisted round their thumbs, at the floor, sideways at each other. They were starting to feel silly. McKenna was bringing them back.

‘Alison has been exposed to a substance that triggered her allergies. Presumably, if she has just been to the toilet, it was either a hand soap or a product used by the cleaning staff. We will investigate this and make sure the trigger is removed.’

McKenna still hadn’t looked at us. Bold kids get ignored. Talking to us too, though, or at us.