Loki has fled Asgard in quest of Yggdrasil, the Tree of Nine Realms. The tree possesses the power of the universe and is hidden on Earth. Loki intends to kill the tree and transplant it in his image with the assistance of the wolf-god Fenrir so that he will have absolute power. Thor must now follow Loki to Earth to engage an epic battle that will determine the fate of the two realms.