Maybe, as long as I can keep my eyes open, I’ll get more time with Mum …

I have no clue if it’ll work, but it’s worth a try. Unfortunately, at that exact moment, she tosses the remote control over to me and stands up.

‘Right. I’m bushed.’

‘No, wait … Don’t you want to stay till the end of the film?’

‘I think I can guess what happens,’ she yawns. ‘Roger gets his end away after delivering an appallingly sexist one-liner.’

I stand up too. I’m suddenly desperate not to let her go. ‘Well, we don’t have to watch the film, then … We can just talk or play another game or something.’

She laughs. ‘Ben, it’s late. I’m exhausted.’

‘I know, but … Let’s stay up a bit longer. Please. Just a few more minutes.’

I make a decision on the spot: I’m going to tell her. I’m going to tell her what’s happening to me! It’ll sound insane, obviously – ‘The thing is, Mum, I appear to be travelling back through time’ – but I’m sure I can convince her. And then, once I have, I can apologise properly. I can tell her I won’t mean all the awful things I’ll say to her in the future. Maybe there’s even a way to change the future. To stop what will happen to her.

My heart leaps at the thought of it. There’s still time!

‘Let’s just stay up until midnight, OK?’ I say. ‘Just till Christmas Day.’

Mum glances up at the clock. ‘Well, that thing’s slow anyway. It might even be midnight already.’

She pulls out her phone to check. And that’s when everything goes black.

Chapter Eighteen

The feeling is one of being hurled backwards with extreme force.

One second I’m standing upright, the next I’m lying flat on my back on a soft mattress, the entire room shaking around me.

I try to sit up, but I can’t. My head is spinning and I’m gasping for air.

And then, suddenly, the shaking stops. Through the window opposite, I can see exactly what caused it: an orange-and-white Overground train, now thundering off into the distance.

I look around me, and with a sickening jolt I realise that the living room is gone – Mum is gone – and I’m somewhere else entirely.

I shoot bolt upright, my heart hammering like crazy.

Was that it? Is it over? Was that the last time I’ll ever see her?

A tight, cold panic seizes me. There was so much more that I could have said. That I should have said.

The watch is still fixed firmly around my wrist. Clearly, there is no loophole. Asleep or awake, I will jump at one minute to midnight, and there’s nothing I can do about it.