It has been six weeks since Magnus Chase and his friends returned from defeating Fenris Wolf and the fire giants. Magnus has adjusted to life at the Hotel Valhalla - as much as a once-homeless and previously alive kid can. As a son of Frey, the god of summer, fertility, and health. Magnus doesn't exactly fit in with the rest of Odin's chosen warriors, but he has a few good peeps among his hallmates on floor nineteen, and he's been dutifully training for Ragnarok along with everyone else. His days have settled into a new kind of normal.
But Magnus should have known there's no such thing as normal in the Nine Worlds...