Thor begins in the mystical land of Asgard, where Thor, the exceptionally powerful warrior and presumptive successor to the seemingly all-powerful King Odin, is set to ascend to the throne. However, his impulsive and arrogant actions reignite an ancient war with the Frost Giants, who threaten his land and the people of Asgard. As punishment for his recklessness, King Odin banishes Thor to Earth, stripping him of his powers and his mighty hammer, Mjolnir, which gives him the ability to wield the power of lightning. Ultimately, Thor is made human, stripping him of the privileges he is known for.
After being banished, Thor decides to head to New Mexico in the United States on Earth. Shortly after landing, he is accidentally hit by a van driven by an astrophysicist named Jane Foster, as well as her assistant Darcy Lewis and mentor Dr. Erik Selvig. Initially, Thor struggles to adapt to his new life without the powers he is accustomed to. Meanwhile, Thor's hammer, Mjolnir, which has also landed on Earth, attracts the attention of S.H.I.E.L.D., a secretive government agency that is interested in its profound power.
Subsequently, the film shifts back to Asgard, where Thor's brother Loki discovers he is actually the son of the king of the Frost Giants and has only been adopted by Odin, who feels sorry for him. Nevertheless, Loki is angry at Odin and seizes the throne of Asgard during Odin's attempt to rejuvenate his injury, which he calls "Odinsleep." Over time, it becomes clear that Loki is interested in nothing more than attaining power for himself.
The film shifts back to Earth, where Thor is developing a relationship with Jane. With Jane, he attempts to retrieve Mjolnir but ultimately fails, proving he is not yet worthy and not strong enough to wield the hammer's power in his current form. After failing, Thor is resigned to his fate on Earth, accepting that he will die a mortal. As a result, he develops an understanding of the meaning of responsibility and self-sacrifice. In the end, he learns what it means to be human.
Loki sends a destructive automaton, the Destroyer, to Earth to kill Thor and secure his place as the ruler of Asgard. Despite not having any power, Thor decides to confront the Destroyer and save Earth. In doing so, he proves himself worthy of his hammer, Mjolnir, which returns to him, restoring his powers and allowing him to properly fight the Destroyer, whom he ultimately defeats. After getting his powers back, Thor returns to Asgard and confronts Loki, whom he hopes to wrestle control of Asgard from.
In the end, Thor and Loki engage in a battle that will determine control of Asgard. In the process, the Bifrost Bridge, which links Earth (and other realms) and Asgard, is destroyed. In the end, Thor defats Loki and regains control of Asgard, having learned a valuable lesson.
