On the wind is the screeching of the bus’s belly against the cold steel tracks. Still the alarm sounds.

‘You aren’t too late,’ his guide tells him. ‘There’s still a way.’

There’s no urgency to how he says it.

The rails begin to hum under Will’s feet. The coastal express is coming. How long has the bus been stuck now? Twenty seconds? In another twenty, the train will obliterate it.

‘How?’ Will says. He looks down the track behind him. No sign yet, but the rails hum harder. He steps to one side of the track. His guide takes the other side, looking across the rails at Will.

‘You’ve come so far.’

Will nods. It’s been a rollercoaster of a few months.

‘I’m so proud of you. Of me.’

Will looks at the blood-dappled snow where he was standing a moment ago.

‘I know how this ends,’ his guide says. ‘I haven’t known long. But I know now.’

Will can see the lights of the train. It’s rounding the bend, flat out through the driving snow. There’s no way it’ll see the bus. But he already knew that.

‘We can’t save them,’ Will says. The guilt makes his organs feel like they’re being wrung out. He should’ve been on that bus, with everyone else. Thanks to his guide, he isn’t. But he’s failed to change the course of history. They are all about to perish, just as they did before. As will so many people on the train. Will’s only succeeded in saving himself. And he can’t bear it.

‘You can,’ his guide says. ‘I’ve seen it.’

Any second now, Will thinks, that train is going to tear past us. A moment later, it’s going to hit the bus. Hundreds dead. An unimaginable tragedy.

‘I don’t understand,’ Will says, the roar of the train’s engine audible now. ‘We can’t move the bus. We can’t get the people off. What do we do?’

‘We can’t move the bus. But we can stop the train.’

Will faces the direction it approaches from. The driving snow is blinding. He waves his arms frantically. But he knows how futile it is.

‘How? Fucking how? Driver will never see me!’ He’s raising his voice now above the rush of the train.

‘You stop the train,’ his guide says. ‘You will save them.’

Will stares blankly back at him.

‘I don’t understand.’

‘You do,’ his guide says. He sounds sad, resigned.

Will’s about to demand more. But he doesn’t. Because, just like that, he gets it. The answer to that question that’s been bugging him. Why me?

Why is it that he, Will Parks, has been singled out to receive these messages, to grow as a person, to change the course of time? Because he can make the difference.