‘Of course.’

‘Can you get someone else to help out today?’

‘Simona just came in, but it’s been dead so far.’ I hear her catch herself, as if the word ‘dead’ will distress me.

‘Thank you, you’re a star. I’ll definitely be in on Monday, no matter what.’

I retrace my steps to the pier. The concourse by the Eye is thickening with tourists, the winter wonderland open for business. I stand for a minute watching the innocents in their knitted hats and leather gloves, talking one another into a cheeky mulled wine or a hot chocolate with whipped cream. As I wait there, alone and unnoticed, it’s as if I am the one who might have been abducted, not Kit.

There’s no service to St Mary’s outside of rush hour, so I board the next boat to North Greenwich. The tide feels stronger, the water more agitated than earlier. Above, the pearl sky is starting to streak with darker cloud. I’ve never seen the boat this empty. Just me and half a dozen tourists in hooded parkas, their bags strapped across their chests. There’s a family of four – Italian, I think. Two sons, less enthused by the riverscape than their parents are, showing each other stuff on their phones. The parents object at first, then give up trying.

The first thing I do is buy coffee and water and listen to Melia’s voicemails from the past few days, pleas for me to let her know if I’ve seen Kit:

‘I’m sure it’s nothing, but . . .’

‘He’s still not back, can you please call me!’

I text her an apology:

So sorry I missed your calls, my phone was off over

Christmas. This is awful about Kit. I swear I haven’t heard

from him since late Monday night. Please let me know

what I can do to help.

I imagine Parry and Merchison reading it, debating whether it’s a genuine approach by a bewildered lover or the sort of message composed by someone covering his criminal tracks. Of course, I know they won’t be doing anything so sci-fi as reading my texts live. On TV, getting phone records takes a matter of hours, but I’ve read that in reality it’s probably more like days or even weeks; the phone companies drag their heels in their dealings with the police. It will be the other side of New Year, surely. And what about internet search histories? Do the police need the actual devices for that? Will they come to the house and seize all our electronics? I think about the calls and texts and internet searches every one of us makes each day, the inferences to be made, cases to be built.

What the police will do soon enough – today, I’m supposing – is phone Clare. At the very least, they’ll want her to confirm the time of my arrival home on Monday and my whereabouts since. I pray they don’t tell her about Melia and me. If they could just hold fire for a few days, ideally a week.

Even before the boat reaches Tower Bridge, both Steve and Gretchen have phoned, one after the other. I let them go to voicemail and then listen to the messages straightaway.

Steve: ‘Jamie, did you hear Kit’s gone walkabout? Let me know if you hear anything, will you?’

And Gretchen, more distressed: ‘Jamie, is this true about Kit? No one’s seen him since our night out? His phone’s turned off, I just tried. Sorry if I was weird earlier, I had stuff to think about. I’m off to Marrakech for New Year – I hope that doesn’t look bad, but I booked it just before I heard the news and I won’t get a refund if I cancel. Anyway, I’m rambling. Please phone me if there’s any news.’ There’s an odd pause before she rings off, as if she was considering adding something but changed her mind.

Or maybe that’s just me, imagining secrets where there are none. I text her:

Yes, it’s true. I’ve already met with the police. Really hope it’s all some misunderstanding.

I send a similar message to Steve and then sit back, my shoulders sinking low in the seat. I’ve never been so aware of the rise and fall of the vessel; at Canary Wharf it seems to have trouble docking, the deck hands stern-faced as they feed the rope through expert fingers. On the move again, the eastern sky darkens to smoke-grey, as if we’re sailing into a bonfire.

A new text pops up from Clare:

How did it go with the police?

A bit worrying, TBH. Skipping work & heading home.

I’ll try to finish early.

At North Greenwich, the service terminates and I’m thrown off balance by the movement of the pontoon beneath my feet, the swelling tide below. I walk down the eastern side of the peninsula; the riggings of the boats rattle in the wind and jar my nerves. As I pass some of the apartment buildings where I’ve had assignations with Melia, I look up at the blank windows and picture the vacant glazed spaces within, the cold finishes and smart technology that await their occupants. They’re strikingly devoid of decorations, as if the festive season has been cancelled in this place, life lived in the near future. There’s just one figure visible on the matrix of balconies, a woman dressed in running gear with a water bottle in her hand, the railings of her balcony making it look as though she’s behind bars.

I follow the home curve of the river, the Thames Barrier glinting ahead, before I turn inland for the train station at Charlton. On the deserted train, I have four seats to myself and sit calmly, watching southeast London slide by. You’d never guess I was a man who’d once brought a network to its knees, or whatever Twitter claimed happened.

I remember the therapist saying, ‘Could you go on the Tube again if it was just you? An empty carriage, no one else.’

‘Yes,’ I said. ‘I think so.’

‘So your fear is associated with the other passengers as much as with being underground.’

Not a question, nor a judgement. A conclusion.

The memory dislodges a more recent one: that odd segue in the police interview between their warning me about ‘other versions’ of what happened on Monday night and probing the episode on the Tube. Why had they made the association? The discussion might reasonably have proceeded with no reference to the Tube incident at all, so it must have been relevant to some unspecified hypothesis of theirs, something more than a demonstration of my – what was it? – ‘impulsive streak’, that was it.

My imagination twists. What if . . . what if this other passenger had something to do with the earlier event? That one hater who’d emailed me those horrible messages: had something happened to her baby and caused her to develop some psychosis, to become fixated on me? Had she been stalking me? I leave the train, walk alone down the platform. No, it’s a crazy leap, not to mention egocentric. People like me don’t have stalkers.

Do we?

*

Senseless, I know, because Clare won’t be home for hours yet, but it’s with a terrible foreboding that I enter Prospect Square and approach number 15. By the time I’ve put my key in the lock, I’m fully expecting it not to fit, for the locks to have been changed, or at the very least for me to find bin liners of my clothes heaped in the hallway. Smashed photograph frames, my passport savaged, toothbrush snapped in two.

But all is as it should be. My clothes are alongside Clare’s in the wardrobe in the master bedroom and the kitschy photo of us at a tea ceremony in Kyoto remains on the mantelpiece. My passport and toothbrush are intact.