Prologue: Thor awakens in Asgard after the battle with Malekith that claimed Thor’s left arm (issue #1). He is eager to return to battle so Odin calls in Screwbeard the dwarf; the expert craftsman offers a mechanical arm made of Black Uru to replace the missing limb. Odin then reveals that his hammer is gone from the moon—and Thor’s mother is missing….
Now: During the siege of Roxxon Island, the old Thor is challenging the new Thor over the right to wield the hammer. Though she suggests they address the matter at another time, the belligerent Odinson is determined to fight. When she taps his chest with Mjolnir to calm him down, he flies into a rage and the battle is on. The two grapple around the island, watched by bemused Frost Giants. When both Thors are touching the hammer, it comes to life, flying around the room, clobbering giants and it passes original Thor and returns to rest in the hand of the new owner. When the Odinson sees this—a move which Mjolnir had never done when he owned it—he admits that she has been chosen by the hammer. The melancholy Thor asks if she is his mother; she responds by kissing him. She isn’t his mom but he still thinks her familiar. Together they destroy the rest of the giants. Malekith takes his leave, producing Thor’s severed arm, then immolating it. Dario Agger orders the heroes off his property….
Asgardian mages free the heroes trapped in the ice outside. Among them is Thor’s mother and he tells her that he will now be called the Odinson as the newcomer is clearly Thor. The all-new Thor takes off into the sky….
Epilogue: Malekith returns to Roxxon Island where Dario Agger reveals that the giant skull destroyed by the new Thor was a fake designed to be a decoy. Agger produces the real skull of Lauffey and he and Malekith get down to business….