Loki wields Thor's power for his amusement, until Thor, Balder and Sif arrive to stop him. Odin witnesses the clash from Asgard and mistaking, Thor for Loki, transports him home to be punished. Odin refuses to hear Thor speak and sentences him to Hades.
On Earth, Loki grabs Sif, but Balder uses his sword's enchantment to teleport her back to Asgard. There, the Grand Vizier shows her Thor's fate in Mephisto's realm. Initially mistaking Thor for Loki, Mephisto senses his goodness and learns the truth. Mephisto unleashes the globules of madness on Thor, followed by a demoniac beast.
In Asgard, Sif gathers the Warriors Three. They reveal the truth to the Vizier who refuses to interrupt Odin while he broods. Instead he sends the foursome to Mephisto's realm to rescue Thor, but Mephisto shows them that Thor is sealed within enchanted ice.