22. Now

Found something? A hair clip? A body? My heart is going to break out of my chest.

I want to headbutt the steering wheel but instead I slip my hand inside my handbag and press the tip of the clipper file reassuringly under the nail of my index finger.

I swing the car around, heading back to the school again, going as fast as I dare round tight bends that sometimes open up to reveal tractors or a herd of sheep.

I'm gasping for air as I push into the security hut. Mr Whitlow gives me a small smile and security, a middle-aged man who I remember is called Argus, nods. Mr Whitlow and I stand over him and watch his screen.

It shows the corridor on the ground floor, outside the canteen. Today's date and the time blink in the top left corner. It would have been lunch break. The footage is slightly grainy, jerky; pupils mill about with bags and phones and crisp packets. Then I see Jenna, slightly hunched, headphones on, her thumbs tucked into the straps of her red backpack. She comes out of the stairwell and walks into Rose, tall, elegant, her green backpack slung on one shoulder.

They stand, lips moving, students jostling past. Then Jenna grabs Rose's backpack and dumps it out – books, pencil case, lip balm, everything. I can see that they're shouting now and then Jenna throws the empty bag back at her, walks off. Ash and Ava come out of the canteen and go after her.

My heart is pounding. I have never ever seen my baby girl do anything like this. She's usually so happy, calm, gentle. Isn't she?

Then I realise something else. Ash and Ava saw this argument. They didn't tell me.

Jenna goes into the bathroom and the twins wait outside. It's not very clear, but I'm sure Ash laughs. Jenna pushes out again and they follow her down the corridor, off-screen.

‘One second,' says Argus, who clicks something, and then we're looking at the drive. Jenna strides up the screen, past the fountain, and Ash and Ava follow her out onto the lane.

The twins followed her? My throat aches.

Argus flicks to another screen, showing the view around the gates. Jenna's headphones are back on and she keeps going as Ava reaches an arm around her shoulder and then they're gone.