‘Took you long enough,’ he says, but the words sound exhausted rather than aggressive. He sounds like a smoker. ‘You know I reported Danny missing five days ago?’

Thistle and I follow him into the open-plan office. I was expecting the Silicon Valley startup aesthetic—beanbags, pool tables, pets—but instead it’s more like the control room of a nuclear submarine. The only light comes from dozens of monitors filled with statistics and pie charts. Headphoned workers tap urgently at their keyboards. Some are eating a late lunch at their desks.

‘How long has Daniel lived with you?’ Thistle asks.

‘Uh, he was at the apartment when I moved in, three years ago,’ McLean says. ‘I guess maybe five years? His old roommate might know.’

‘We’ll need contact details for him.’

‘Her. I’ll have to talk to the real estate company. They’d have those details.’

McLean leads us into a glass-walled meeting room. No one else in there. A big TV in the corner with a camera on top, for video conferencing. We sit on swivelling chairs with mesh backs.

‘What do you do here?’ Thistle asks casually. ‘For nTangle.’

McLean looks wary. ‘What does that have to do with Daniel?’

Thistle backpedals a little. ‘I mean, do you work long hours? How often do you see Daniel?’

‘Oh. I’m in charge of cyber security, so I work late if there’s ever any kind of major attack on nTangle. But that hasn’t happened in a couple of weeks, so I saw Daniel every day. We used to play Madden most nights.’

‘Your app is free, right?’ I ask. ‘So no one’s bank accounts are attached to it.’

‘Yes, but there are still attacks,’ Daniel says. ‘If they ever got in, hackers could steal users’ photos, their email addresses, their names, data about the places they’ve been, the people they’ve met, their desirability score—all that is worth money. People can use it to create real-seeming profiles on social media, and those profiles can disseminate information for companies, or for political purposes.’

‘Desirability score?’ Thistle says.

‘The ratio of winks to profile views. The app uses this score to pair up people who are equally desirable. If an attractive user keeps getting paired up with ugly users, they might uninstall the app. And if the attractive users leave, the unattractive ones won’t hang around for long. Users can’t see desirability scores, not even their own—unless they work here, obviously. I’m a point one eight.’ When neither of us looks impressed, he says, ‘Anything over point one five is really good for a man.’

‘Different people have different tastes, though,’ Thistle says.