"Magnus and friends help the god of thunder find his missing weapon before all Muspellheim breaks loose"-- "Thor's hammer is missing again. The thunder god has a disturbing habit of misplacing his weapon--the mightiest force in the Nine Worlds. But this time the hammer isn't just lost, it has fallen into enemy hands. If Magnus Chase and his friends can't retrieve the hammer quickly, the mortal worlds will be defenseless against an onslaught of giants....

Magnus Chase has always been a troubled kid. Since his mother's mysterious death, he's lived alone on the streets of Boston, surviving by his wits, keeping one step ahead of the police and the truant officers. One day, he is tracked down by a man he's never met -- a man his mother claimed was dangerous. The man tells him an impossible secret: Magnus is the son of a Norse god. The Viking myths are true. The gods of Asgard are preparing for war. Trolls,...