Resolution

Introduced by a character from the story:

"My friend and his twin brother have gone crazy. I think one of them might be Marcus - or, at least, who Marcus is now.

"We were at their seventh birthday party and they just started stabbing and killing the other children. They even killed their own mum and dad!

"Me and Stephen only just got away but they're chasing after us. I'm Martin, Martin Dier, by the way. You have met me before but probably don't recognise me.

"And it's not just the twins. They've got a couple of friends with them - a bigger boy and a girl who's batshit crazy. She swears a lot.

"If they catch us, they'll kill us. You'd better run or they'll kill you too!"