It starts Chris Hemsworth as Thor.
The Asgardians are a race of aliens that can live for many millenia who own an interdimensional travel device called the Bifrost, which opens a rainbow-like wormhole that allows Asgardians to travel across 9 different dimensions. Centuries ago they visited Earth, when they did the human civilization at the time mistook the Asgardians visitors to be celestial beings and created the Norse Mythology. The Asgardians saved Earth from the Frost Giants from Jotunhelm and Asgardian king Odin took their Ice weapon that could freeze an entire planet. Years later Odin told his two sons Thor and Loki that one day one of them would become king.
In the present, Thor is about to be crowned the new king when suddenly two Frost Giants attack the palace trying to steal the Ice Treasure but are killed by the Destroyer, a giant mech that defends Odin's treasure room. The incident however interrupts Thor's coronation much to his rage. Angered, thor convinces Loki and his friends to go to Jotunhelm and confront the Ice king about the incident, despite their protests. Bifrost guardian Heimdalr warns them that the trip is a bad idea because Asgard and Jotunhelm have had a truce for centuries, but allows them to go because he's worried that the Frost Giants managed to sneak into Asgard without him noticing. He also asks them to be quick because if Bifrost remains open for too long it could destroy Jotunhelm.
In Jotunhelm, the Ice King Laufey assures the Asgardians that the Frost Giants were rebels and also warns tham that their visit could be taken as a war threat. Thor immediately loses his patience and attacks the Frost Giants. During the fight Loki touches a Frost Giant, when he does his skin turns into a Frost Giant's for a brief moment. Odin appears takes everyone back to Asgard. Back home, Odin angrily scolds Thor for his irresponsible immaturity, strips him of all his powers, and banishes him to Earth which in turns means Loki is the new heir of the throne. He also puts a magic spell on Thor's hammer the Mjolnir; "Whosoever holds this hammer, if he be worthy, shall possess the power of Thor." and sends the hammer to Earth.
In Earth, scientist Jane Foster, her old teacher Erik Selvig, and her assistant Darcy Lewis are investigating strange thunderstorms in New Mexico that indicate the possibility of wormholes when their van hits Thor, who had just arrived on Earth. The three assume Thor is a drunk insane man and take him to a hospital. Around the same time Mjolnir lands nearby, the local residents mistake it for a meteorite but no one can lift it. S.H.I.E.L.D. quickly appears and quarantees the area to study the "meteorite". Thor stays at Jane for the time being and hears about "a hammer shaped meteorite that no one can lift" which he immediately identifies as Mjolnir. Selvig remains wary of Thor because he keeps talking about Norse Mythology but Janes agrees to take him to where the hammer is.
In the mean time, Loki admits to Thor's friends that he was the one who called Odin when they sneaked into Jotunhelm but insists that he didn't mean wrong. He continues to obsess about what happened to him during that fight and eventually confronts Odin about it. Odin reveals that during the last war with Jotunhelm Odin found an abandoned Frost Giant baby which he adopted and casted a spell on to make him look like an Asgardian; Loki is a Frost Giant and in fact Laufey's son. Odin hoped Loki would bring true peace bewteen the two species but now realizes his plan failed when suddenly he falls comatose. Loki takes the throne of Asgard for the time being. Thor's friends begin to suspect Loki is up to something fishy. Loki goes to Jotunhelm to inform Laufey that with Odin comatose now's the right time for them to invade Asgard and recover their Ice Treasure. Heimdalr also becomes suspicious of Loki because he couldn't track his actions.
Thor effortlessly takes down S.H.I.E.L.D.'s agents and reaches Mjolnir but finds out he can't lift it either because he's no longer worthy of the throne, and is captured. Loki disguises as a S.H.I.E.L.D. agent and uses his illusion powers to talk to Thor in private. Loki lies to trick Thor into thinking Odin is dead and the truce with Jotunhelm will only stay if Thor remains banished. Selvig manages to get Thor out of S.H.I.E.L.D.'s prison, later that night Thor and Jane get closer as he talks to her about Asgard and the 9 dimensions. Heimdalr and Thor's friends all agree that Loki is up to no good so Heimdalr sends them to Earth, right after that Frost Giants appear, freeze Heimdalr, and Loki sends the Destroyer after Thor. Laufey prepares to kill Odin but Loki backstabs Laufey and kills him to make it seem like he just saved Odin and all of Asgard.
Thor reunites with his friends but the meeting is short-lived because the Destroyer starts destroying the town. Powerless, Thor can't do anything but watch as his friends try to fend off the Destroyer in vain. Thor contacts Loki through the Destroyer and pleas him to spare Earth and only kill him. Loki agrees and mortally injures Thor with the Destroyer much to Jane's horror. At that moment, the spell on Mjolnir determines that Thor's self-sacrifice has made him worthy once more so the hammer immediately flies to Thor, reinvigorating him and restoring all of his powers. With his power back, Thor destroys the Destroyer. Before going back to Asgard he promises Jane to come back after solving the situation there. Heimdalr thaws himself so he can open the Bifrost for them.
Now having returned to Asgard, Thor confronts Loki about his deception and assasination attempt, he also calls him out for letting the Frost Giants into the city. Loki escapes and forcefully activates the Bifrost at max power, causing Jotunhelm to quickly start collapsing. In Earth Jane's equipment detect the Bifrost's unusual activity making her wory. Loki snaps claiming that all he wanted was the throne so that he could stop being jealous of Thor and attacks him. The two brothers are evenly matched until Thor uses Mjolnir to pin down Loki. Loki remains confident that Jotunhelm can't be saved anymore. Thor reluctantly destroys the Bifrost to save Jotunhelm, but also destroys his chance to go back to Jane.
The bridge connecting Asgard to Bifrost collapses but Odin appears and saves his two sons before the fall into the cosmic abyss. Loki desperately begs Odin to accept him as heir and exclaims that all his actions were done just so Odin would be proud of him. Odin simply says that he's dissapointed in Loki, causing Loki to let himself fall to the abyss. In the aftermath Odin tells Thor that he'll be a good king one day, but Thor decides not to take the throne for the time being and Heimdalr believes that there's still a way for Thor to go back to Earth without Bifrost, and reveals that Jane is working on interdimensional travel research so she can come to Asgard one day.
In the post-credits scene S.H.I.E.L.D. invites Selvig to study "The Tesseract" and Loki, who's survived his fall from Bifrost, comes into contact with the Chitauri army.
Why it Rocks
- The movie brings an interesting question: What if the gods mentioned in mythologies and religions were actually aliens that visited Earth long ago and the human civilizations at the time mistook them for celestial beings?
- Chris Hemsworth portays Thor very well. He begins the movie as a spoiled selfish arrogant person who throughout the movie learns to be humble.
- Gorgeous visuals of Asgard.
- Blends some of the basic myths of Norse Mythology with the Marvel lore and scientific research of interdimensional travel.
- Introduces Loki, one of the most popular villains in the MCU.
- Hints through out the movie indicate that it takes place around the same time as Iron Man 2 and shortly before Captain America is defrosted at the end of Captain America: First Avenger.