To celebrate the “festive season of Thor’s birth,” the three Norns (Urd, Skuld, Verdanda) retell details from the early life of Thor. The story is broken into 6 chapters.
CHAPTER 1: “The Birth of Thor” In the distant past, Odin travels to Midgard with a proposition for Jord, a manifestation of Gaea, the Elder God. He proposes that together they could produce an incredibly powerful offspring unlike any other god. Jord agrees that since all Asgardians derived from Odin’s power alone, such an offspring would be unprecedented and mighty. After Odin uses his powerful spear, Gungnir, to carve a cave deep into the earth, Jord eventually gives birth to Thor and hands him to Odin. Odin bids farewell to Jord and brings Thor to Asgard, where he presents his son to his wife Frigga. Frigga vows to raise Thor as her own.
CHAPTER 2: “The Treasures of the Gods” An eight-year-old Thor asks Odin to recount the story of Gungnir’s creation, while Loki considers how he might learn some secret knowledge from the story. Odin then describes how, ages ago, the dwarves captured beams of sunlight in their furnace and forged them into Gungnir. Odin then explains to Thor and Loki how none but he can wield it. When Odin leaves Gungnir unattended, Loki decides to touch it. When he does, the spear falls to the ground and a magical serpent emerges from it. Thor slays the serpent, which vanishes once it is killed, as Odin returns. Odin then reveals that he had planned to commission new treasures from Brokk and Eitri, descendants of the dwarves who created Gungnir, but due to his mischief Loki will not receive any gifts. Odin sends Thor alone to the dwarves to deliver the message, but Loki follows him by shape-shifting into a raven. When Thor reaches the abode of the dwarves, Loki changes again, this time into a moth. Loki plans to interfere with the dwarves so that their creations are spoiled. The dwarves create Gullinbursti, a golden, living boar; Draupnir, a golden arm-band that magically replicates itself 9 times, every 9 days, for eternity; and Mjolnir. As they craft Mjolnir, Loki finally succeeds in distracting Brokk, which results in the hammer having a shorter handle than planned. Thor and the dwarves journey back to Asgard, where they present the treasures to Odin. Odin is pleased, and adds powerful enchantments to Mjolnir: it can control the elements, it will always return to the hand of its wielder, and only someone worthy can lift it. Odin declares that it will be reserved for Thor once he proves himself worthy, and Loki silently vows that he will do whatever it takes to prevent that day from coming.
CHAPTER 3: “The Winning of Mjolnir” Thanks to a number of various heroic feats, Thor eventually proves himself worthy of wielding Mjolnir. When Odin finally presents him with the hammer, Thor takes off from the celebration to try it out. As he flies over the kingdom of Asgard, Thor sees a legion of “boar gods,” led by Gullin, secretly marching against Asgard. Thor descends and uses Mjolnir to fight them off, preventing the attack. When he returns to Asgard, none are aware of Thor’s first feat with Mjolnir, but they all toast his many battles to come.
CHAPTER 4: “The Mischief of Loki Against Sif” One evening, Loki watches a blissful Thor and blonde-haired Sif expressing their love for one another. Disgusted, Loki transforms himself into a nightingale and lands upon Sif’s shoulder. When Sif says goodnight to Thor, she brings the nightingale to her bedchamber to sing for her. Once she falls asleep, the bird changes back into Loki, who cuts off all of her golden hair. In the morning, Sif refuses to come out to see Thor because she thinks she is ugly. Thor immediately suspects Loki. As soon as Thor confronts Loki, he admits his guilt. Thor gives Loki one day to restore Sif’s hair, so Loki quickly rides to the dwarves Brokk and Eitri. When Loki tells the dwarves that he has nothing to pay them for the hair, Eitri says that he will make the hair out of “naught,” or nothing. Then, Eitri pulls the darkness of night down into their cave and creates magic hair out of the blackness. The next day, Thor is angry that Loki gave him black hair instead of blonde, but Loki reminds him that he never specified the color. However, when Sif emerges with the new black hair, Thor says that she is more beautiful than ever.
CHAPTER 5: “The Worship of Midgard” During the Viking-era, Thor discusses with Odin how he hears his praise rising up from Midgard even though he has never visited the warriors who worship him there. Despite his concern that the adulation might go to the young Thor’s head, Odin grants him permission to visit the realm below. On Earth, Thor spends years going on raids with the Vikings and enjoys leading them to victory. After one short battle, Thor is curious to see what kind of foe was defeated so quickly. He enters a burning monastery and is furious to find that innocent blood has been spilt in his name. Thor returns to Asgard and realizes that his values—such as battle for pleasure—should not be encouraged in a world where mortals die so easily. Thor vows to leave the world of mortals for good in an attempt to atone for the carnage that took place in his name.
CHAPTER 6: “The Humbling of Thor” Eventually, Thor’s warrior ways return, and he becomes a headstrong prince concerned only in his own conceit. Odin is dismayed, and decides that he must teach Thor humility. Odin demands that Thor relinquish Mjolnir. He then strips Thor of his memories and godly identity, transforming him into crippled medical student Donald Blake. After ten years pass on Earth, Odin secretly guides Blake to Norway, where he recovers Mjolnir. However, Odin does not yet reveal his true identity. Odin prefers that Thor believe he is a mortal with the power of a god so that he will continue to learn humility, and so that he can learn to reign in his formidable strength around his less-powerful mortal companions. After more years pass, Odin finally removes his spell of forgetfulness. Even though he now remembers everything, Thor decides to remain on Earth for the time being to continue to make up for his past misdeeds.