A new wave of emails with attachments had come in late last night and this morning. Word must have started to spread about Jamie. But still no photos in the location and time-window she needed. Pip glanced up: five minutes until the bell, enough time to go through another email.

The next one was from Hannah Revens, from Pip’s English class.

Hey Pip, it said. Someone told me this morning you’re looking for Connor’s missing brother and that he was at the calamity on Friday. This video is super embarrassing – apparently I sent it to my boyfriend at 9:49 when I was already super drunk – please don’t show it to anyone. But there’s a guy in the background I don’t recognize. See you at school x

A prickle of nervous energy crawled up the back of Pip’s neck. The time window, and a guy Hannah doesn’t recognize. This could be it: the break. She thumbed on to the attached file and pressed play.

The sound blared into her ear: loud music, a horde of chattering voices, bursts of jeering and cheering that must have come from the beer pong game in the dining room. But this video was taken in the living room. Hannah’s face took up most of the frame, pointing the phone down at herself from an outstretched arm. She was leaning against the back of a sofa, opposite the one Jasveen was sitting on at 9:38 p.m., the end of which was just visible in the background.

Hannah was alone, the dog filter from Instagram applied to her face, pointy brown ears buried in her hair, following her as she swung her head around. The new Ariana Grande song was playing, and Hannah was lip-synching to it. Very dramatically. Air grabs and eyes screwed shut when the song demanded it.

This wasn’t a joke, was it? Pip kept watching, searching the scene behind Hannah’s head. She recognized two of the faces back there: Joseph Powrie and Katya Juckes. And judging by the positions of the sofas, they must have been standing in front of the fireplace, which hadn’t quite made it into the shot. They were talking to another girl with her back to the camera. Long dark straightened hair, jeans. That could be dozens of people Pip knew.

The clip was almost finished, the blue line creeping along the progress bar towards the end. Six seconds to go. And that’s when two things happened at the exact same time. The girl with the long brown hair turned, started to walk away from the fireplace, towards Hannah’s camera. Simultaneously, from the other side of the frame, a person crossed towards her, walking quickly so all you really catch is the blur of their shirt and a head floating above. A burgundy shirt.

As the two figures were about to collide, Jamie reached out to tap the girl on the shoulder.

The video ended.

‘Shit,’ Pip whispered into her sleeve, drawing Connor’s attention. She knew exactly who that girl was.

‘What?’ he hissed.

‘ “Someone”.’

‘Huh?’

The bell rang and the metallic sound sliced right through her, making her wince. Her hearing was always more sensitive on not-enough sleep.

‘In the hall,’ she said, packing her textbook into her bag and disentangling herself from the earphones. She stood up and shouldered her bag, missing whatever homework task Mr Clark was assigning them.

Being at the back meant being last to leave, waiting impatiently for everyone else to spill out of the classroom. Connor followed Pip into the corridor and she guided him over to the far wall.

‘What is it?’ Connor asked.

Pip unwound her earphones, jamming them one by one into Connor’s pointy ears.

‘Ouch, be careful, would you?’ He closed his hands around his ears to keep the sound in as Pip held up her phone for him and pressed play. A tiny smirk flickered across his face. ‘Wow, that’s embarrassing,’ he said after a few seconds. ‘Is that why you wanted to show m—’

‘Obviously not,’ she said. ‘Wait for the end.’

And when it came, his eyes narrowed and he said, ‘Stella Chapman?’

‘Yep.’ Pip tugged the earphones out of his ears too hard, making him ouch again. ‘Stella Chapman must be the “someone” he spotted at the memorial and followed to the party.’

Connor nodded. ‘So what do we do now?’

‘Find her at lunch and talk to her. Ask how they know each other, what they talked about. Why Jamie followed her.’

‘OK, good,’ Connor said, and his face changed slightly, like the muscles beneath had shifted, loosened. ‘This is good, right?’

‘Yeah,’ she said, though good might not be the right word.

But at least they were finally getting somewhere.

‘Stella?’

‘Oh, hi,’ Stella replied, mid-mouthful of Twix. She narrowed her brown almond-shaped eyes, her perfect cheekbones made even sharper by the bronzer she’d swiped over her tanned skin.

Pip had known exactly where to wait for her. They were locker neighbours, Chapman just six doors over from Fitz-Amobi, and they greeted each other most mornings, their hellos always book-ended by the awful screech of Stella’s locker door. Pip was ready for it this time, as Stella opened the door and deposited some books inside.

‘What’s up?’ Stella’s eyes trailed away, over Pip’s shoulder to where Connor was standing, boxing her in. He looked ridiculous, hands on his hips like he was some kind of bodyguard. Pip flashed him an angry look until he stepped back and relaxed.

‘You on the way to lunch?’ asked Pip. ‘I was wondering if I could talk to you about something.’

‘Er, yeah, I’m heading to the cafeteria. What’s wrong?’

‘Nothing,’ Pip said, casually, walking Stella down the hall. ‘Just wondered whether I could borrow you for a few minutes first. In here?’ Pip halted, pushing open the door of a maths classroom she’d already checked was empty.

‘Why?’ The suspicion was clear in Stella’s voice.

‘My brother’s missing,’ Connor butted in, hands going to his hips again. Was he trying to look intimidating? Because it wasn’t working for him at all. Pip glared at him again; normally he was good at reading her eyes.

‘You might’ve heard that I’m looking into his disappearance?’ Pip said. ‘I just have a few questions for you about Jamie Reynolds.’

‘I’m sorry.’ Stella shuffled uncomfortably, picking at the ends of her hair. ‘I don’t know him.’

‘Bu—’ Connor started but Pip cut him off.

‘Jamie was at the calamity party on Friday. It’s currently the last time he was seen,’ she said. ‘I’ve found a video in which Jamie comes over to talk to you at the party. I just want to know what you talked about, how you know each other. That’s all.’

Stella didn’t answer, but her face said everything she wouldn’t: her eyes widened, lines disturbing her smooth forehead.

‘We really need to find him, Stella,’ Pip said gently. ‘He could be in trouble, real trouble, and anything that happened that night might help us work out where he’s gone. It’s . . . it’s life or death,’ she said, refusing to look Connor’s way.

Stella chewed her lip, eyes spooling as she made up her mind.

‘OK,’ she said.

Stella:

Is this OK?

Pip: