The second book in this number one; bestselling series from the creator of Percy Jackson. Thor's hammer is missing again. The thunder god has a habit of misplacing his weapon - which happens to be the mightiest force in the Nine Worlds. But this time the hammer isn't just lost; it has fallen into enemy hands. Magnus Chase and his friends must find it; fast. If they don't; the mortal worlds will be defenceless against an onslaught of giants; and the Nine Worlds will burn. But the only person who can help them is the gods' worst enemy; Loki - and the price he wants is very high.