Alex is a normal, everyday kid, living in a normal, everyday city. Axel is a monster-slaying hero, living in a world of magic. Unfortunately, when the two boys mysteriously swap places, each of them ends up being mistaken for the other. With zero experience of heroism, Alex is thrust into an epic quest to defeat the evil Felonius Gloam, who has stolen the Book of Lifetales and is using it to unravel the very fabric of the world of Aërth. Meanwhile, Axel is faced with double maths, a gran who's six months behind on the rent, and a crucial chess tournament he's got to win – when he doesn't even know how to play. Can the two boys complete their Impossible Quests and find a way back to their own lives, or will they both discover they don't have a life to come back to...?