‘So you can be … different people, I suppose. Flipside 1223 is a sort of alias. Her other e-mails all went to Flip-dot-Balfour.’

‘So what does it mean?’

Siobhan expelled air. ‘That’s what I’m wondering. Maybe it means she had a side we don’t know about. There’s not a single saved message from her or to her in the name of Flipside 1223. So either she’s been erasing them as she goes, or else this got to her by mistake.’

‘Doesn’t look like coincidence, does it, though?’ Rebus said. ‘Her nickname’s Flip.’

Siobhan was nodding. ‘Hellbank, Stricture, Pagan Omerta …’

‘Omerta’s the mafia code of silence,’ Rebus stated.

‘And Quizmaster,’ Siobhan said. ‘Signs herself or himself QuiM. Little touch of juvenile humour there.’

Rebus looked at the message again. ‘Beats me, Siobhan. What do you want to do?’

‘I’d like to track down whoever sent this, but that’s not going to be easy. Only way I can think of is to reply.’

‘Let whoever it is know that Philippa’s gone missing?’

Siobhan lowered her voice. ‘I was thinking more along the lines of her replying.’

Rebus was thoughtful. ‘Think it would work? What would you say?’

‘I haven’t decided.’ The way she folded her arms, Rebus knew she was going to do it anyway.

‘Run it past DCS Templer when she gets in,’ he cautioned. Siobhan nodded and made to leave, but he called her back. ‘You went to uni. Tell me, did you ever mix with the likes of Philippa Balfour?’

She snorted. ‘That’s another world. No tutorials or lectures for them. Some of them I only ever saw in the exam hall. And you know what?’

‘What?’

‘The sods always passed …’

That evening, Gill Templer hosted a celebratory gathering at the Palm Court in the Balmoral Hotel. A tuxedoed pianist was playing in the opposite corner. A bottle of champagne sat in an ice-bucket. Bowls of nibbles had been brought to the table.

‘Remember to leave space for supper,’ Gill told her guests. A table in Hadrian’s had been booked for eight-thirty. It had just gone half past seven, and the last arrival was coming through the door.

Slipping off her coat, Siobhan apologised. A waiter appeared and took the coat from her. Another waiter was already pouring champagne into her glass.

‘Cheers,’ she said, sitting down and lifting the glass. ‘And congratulations.’

Gill Templer lifted her own glass and allowed herself a smile. ‘I think I deserve it,’ she said, to enthusiastic agreement.