As Thor and the Warriors Three, guided by the troll Kygar, continue their quest for the Well at the Edge of the World, they are met by a beautiful woman who introduces herself as Satrina. Ignoring Kygar’s warnings not to trust her, the warriors follow Satrina to her home, the Darkhold, where she promises them some much needed rest and recuperation. Inside the castle, Satrina bids the warriors admire a beautiful charm. When they look upon it, a red mist flows out and knocks the warriors out, a ploy which Satrina believes will please her master Kartag. When Thor wakes, he does not remember his quest, but sees the Warriors Three celebrating surrounded by food and beautiful women. Kygar, however, finds Thor and again warns him against trusting Satrina. As he does, Satrina zaps Kygar with a magical bolt, killing him but jogging Thor’s memory. He challenges Satrina, and goes to rally the Warriors Three—seeing now that they are surrounded not by beautiful women, but by hideously deformed creatures disguised by magic! When Thor strikes one of the monsters, the Warriors Three accuse him of attacking a defenseless woman, and take arms against him. Thor holds the Warriors Three back with a bolt from Mjolnir, then confronts Satrina. When she retreats, the illusion is lifted from the Warriors Three, and their quest continues.
Meanwhile, the army of Asgard is mobilizing to face Mangog. As Odin watches the army from his chamber and reflects on the futility of the task before him, Hela appears in a cloud of smoke. She deduces Odin’s plot to protect Thor by sending him on an impossible quest, and tells Odin that Thor will never forgive him for sending him away from Asgard’s final battle. Odin, of course, knew this when he sent him. Odin finally leads the charge against Mangog, who dispatches the entire force in one blow by obliterating the bridge they were crossing. In the rubble, Odin finds his friend, the elder warrior Khan, dead. With steely resolve, Odin realizes what lengths he will have to go to in order to stop Mangog.
At the same moment in Blackworld, Lady Sif and Hildegarde are still unable to find an inn that will take them in. Everyone they encounter in the village simply warns that “he” is coming. As they wander the streets, a roving band of knights attacks them. Sif is thankful, since battle is the only thing she loves as much as Thor. Hildegarde and Sif quickly defeat the men, and continue to seek out the nature of the world upon which they have found themselves.
Back in Kartag’s realm, Thor and the Warriors Three continue their quest. Suddenly, they are attacked by a fearsome dragon called Redguard, who reveals himself to be yet another servant of Kartag. The warriors cannot defeat Redguard, and are soon surrounded by flames. Thor puts two and two together and figures out that Redguard is a creation of Satrina’s. The Warriors Three grab hold of Thor, who uses Mjolnir to fly away from Redguard. Nearby, they find Satrina waiting for them. Satrina is amused to discover that Thor does not know anything about the Well he seeks, and finally offers to take them there herself. Although they don’t trust Satrina, they believe her and decide to follow her.
In Asgard, Odin mourns Khan’s death on the battlefield when Hela shows up to claim him. For a moment, Odin pauses to watch Mangog decimate his forces, then “something within [his] noble soul doth break.” Odin cries out that he has seen too many good men die, and unleashes the full force of his power upon Mangog. For the sake of a thousand universes, he says, he must stop Mangog even if it means destroying his own realm. Odin’s voice echoes through the cosmos as Asgard is seemingly destroyed, and even in far off Blackworld Sif and Hildegarde see a mighty nova bursting in the sky. Elsewhere, Thor and the Warriors Three finally reach their quest’s end as Satrina leads them to Kartag. Thor enters Kartag’s dark cavern alone, where Kartag declares that Thor will die by his hand.