‘I’m always available for sneakiness. What d’you need?’

‘Is Naomi in?’

‘No, out in London. Why? ’ Suspicion crept into Cara’s voice.

‘OK, sworn to secrecy?’

‘Always. What’s up?’

Pip said, ‘I’ve heard rumours about old calamity parties that might give me a lead for my EPQ. But I need to find proof, which is where the sneakiness comes in.’

She hoped she’d played it just right, omitting Max’s name and downplaying it enough that Cara wouldn’t worry about her sister, leaving just enough gaps to intrigue her.

‘Oooh, what rumours?’ she said.

Pip knew her too well.

‘Nothing substantial yet. But I need to look through old calamity photos. That’s what I need your help with.’

‘OK, hit me.’

‘Max Hastings’ Facebook profile is a decoy, you know for employers and universities. His actual one is under a fake name and has really strict privacy settings. I can only see things that Naomi is tagged in as well.’

‘And you want to log in as Naomi so you can look through Max’s old photos?’

‘Bingo,’ Pip said, sitting down on her bed and dragging the laptop over.

‘Can do,’ Cara’s voice trilled. ‘Technically we’re not snooping on Naomi, like that time when I just had to know whether ginger Benedict Cumberbatch-alike was her new boyfriend. So this doesn’t technically break any rules, Dad . Plus, Nai should learn to change her password sometime; she has the same one for everything.’

‘Can you get on to her laptop?’ Pip said.

‘Just opening it now.’

A pause filled with the tapping of keys and a clicking mousepad. Pip could picture Cara now with that ridiculously oversized topknot she always wore on her head when she was dressed in pyjamas. Which was, in Cara’s case, as often as physically possible.

‘OK, she’s still signed in here. I’m on.’

‘Can you click on to security settings?’ asked Pip.

‘Yep.’

‘Uncheck the box next to log-in alerts so she won’t know I’m logging in from a new machine.’

‘Done.’

‘OK,’ Pip said, ‘that’s all the hacking I need from you.’

‘Shame,’ Cara said, ‘that was much more thrilling than my EPQ research.’

‘Well, you shouldn’t have chosen to do yours on mould,’ Pip said.

Cara read out Naomi’s email address and Pip typed it into the Facebook log-in page.

‘Her password will be Isobel0610,’ Cara said.

‘Excellent.’ Pip typed it in. ‘Thanks, comrade. Stand down.’

‘Loud and clear. Although if Naomi finds out, I’m dobbing you in it straight away.’

‘Understood,’ said Pip.

‘All right, Plops, Dad’s yelling. Tell me if you find out anything interesting.’

‘OK,’ Pip said, even though she knew she couldn’t.

She dropped the phone and, leaning over her laptop, pressed the Facebook log-in button.

Glancing quickly at Naomi’s newsfeed, she noticed that, like her own, it was filled with cats doing silly things, quick-time recipe videos and posts with ungrammatical motivational quotes over pictures of sunsets.

Pip typed Nancy Tangotits into the search bar and clicked on to Max’s profile. The spinning loading circle on the tab disappeared and the page popped up, a timeline full of bright colours and smiling faces.

It didn’t take long for Pip to realize why Max had two profiles. There’s no way he would have wanted his parents to see what he got up to away from home. There were so many photos of him in clubs and bars, his blonde hair stuck down on his sweaty forehead, jaw tensed and his eyes reeling and unfocused. Posing with his arms round girls, sticking his stippled tongue out at the camera, drops from spilled drinks splattered on his shirts. And those were just the recent ones on his timeline.

Pip clicked on to Max’s photos and began the long scroll down towards 2012. Every eighty or so photos down, she had to wait for the three loading bars to take her further into Nancy Tangotits’ past. It was all much of the same: clubs, bars, bleary eyes. There was a brief respite from Max’s nocturnal activities with a series of photos from a ski trip, Max standing in the snow wearing just a Borat mankini.

The scrolling took so long that Pip propped up her phone and pressed play on the true crime podcast episode she was halfway through. She finally reached 2012 and took herself right back to January before looking through the photos properly, studying each one.

Most photos were of Max with other people, smiling in the foreground, or a crowd laughing as Max did something stupid. Naomi, Jake, Millie and Sal were his main co-stars. Pip lingered for a long time on a picture of Sal flashing his brilliant smile at the camera while Max licked his cheek. Her gaze flicked between the two drunk and happy boys, looking for any pixelated imprint of the possible and tragic secrets that existed between them.

Pip paid particular attention to those photos with a crowd of people, searching for Andie’s face in the background, searching for anything suspicious in Max’s hand, for him lurking too close to any girl’s drink. She clicked forward and back through so many photos of calamity parties that her tired eyes, scratchy from the laptop’s drying white light, turned them into flipbook moving pictures. Until she right arrowed on to the photos from that night and everything became sharp and static again.