Thor: Ragnarok is a 2017 American superhero film based on the Marvel Comics character Thor, produced by Marvel Studios and distributed by Walt Disney Studios Motion Pictures. It is the sequel to 2011’s Thor and 2013’s Thor: The Dark World, and is the seventeenth film of the Marvel Cinematic Universe (MCU). The film is directed by Taika Waititi from a screenplay by Eric Pearson and the writing team of Craig Kyle and Christopher Yost, and stars Chris Hemsworth as Thor alongside Tom Hiddleston, Cate Blanchett, Idris Elba, Jeff Goldblum, Tessa Thompson, Karl Urban, Mark Ruffalo, and Anthony Hopkins. In Thor: Ragnarok, Thor must escape the alien planet Sakaar in time to save Asgard from Hela and the impending Ragnarök.
Two years after the Battle of Sokovia, Thor has been unsuccessfully searching for the Infinity Stones, and is now imprisoned by the fire demon Surtur. Surtur reveals that Thor’s father Odin is no longer on Asgard, and that the realm will soon be destroyed in the prophesied Ragnarök, once Surtur unites his crown with the Eternal Flame that burns in Odin’s vault. Thor defeats Surtur and claims his crown, believing he has prevented Ragnarök.
Thor returns to Asgard to find his brother Loki posing as Odin. Thor forces Loki to help him find their father, and with directions from Stephen Strange on Earth, they locate Odin in Norway. Odin explains that he is dying, and that his passing will allow his firstborn child, Hela, to escape from a prison she was sealed in long ago. Hela had been the leader of Asgard’s armies, and had conquered the Nine Realms with Odin, but had been imprisoned and written out of history after Odin feared that she had become too ambitious. Odin subsequently dies, and Hela, who is immediately released from her imprisonment, appears. She destroys Thor’s hammer Mjolnir, and when Thor and Loki attempt to flee through the Bifröst Bridge, she pursues them and forces them out into space to die. Hela arrives in Asgard, destroying its army and the Warriors Three; resurrects the ancient dead who once fought with her, including her giant wolf Fenris; and appoints the Asgardian Skurge as her executioner. She plans to use the Bifröst to expand Asgard’s empire, but Heimdall covertly steals the sword that controls the Bridge, and hides away with the rest of Asgard’s citizens.
Thor crash-lands on Sakaar, a garbage planet surrounded by wormholes. He is captured by a bounty hunter named Scrapper 142, and taken to serve as a gladiator for the planet’s ruler, the Grandmaster, with whom Loki has already become ingratiated. Thor recognizes 142 as one of the Valkyrior, a legendary force of female warriors who were killed defending Asgard from Hela long ago. Thor is forced to compete in the Grandmaster’s Contest of Champions, facing his old friend the Hulk. Summoning lightning, Thor almost defeats the Hulk but the Grandmaster sabotages the fight to ensure the Hulk’s victory. Still enslaved, Thor attempts to convince Hulk and 142 to help him save Asgard, but neither is willing. He soon manages to escape the palace and finds the Quinjet that brought Hulk to Sakaar. Hulk follows Thor to the Quinjet, where a recording of Natasha Romanoff makes him transform back into Bruce Banner for the first time since Sokovia.
The Grandmaster orders 142 and Loki to find Thor and Hulk, but the pair come to blows and Loki forces her to relive the deaths of her fellow Valkyrie at the hands of Hela. Deciding to help Thor, she takes Loki captive to prove her goodwill. Unwilling to be left behind, Loki provides the group with the means to steal one of the Grandmaster’s ships. They then liberate the other gladiators who, led by Korg and Miek, stage a rebellion. Loki attempts to betray his brother to gain a reward from the Grandmaster, but Thor anticipates this and leaves him behind, where Korg and the gladiators soon find him. Thor, Banner, and 142 escape through a wormhole to Asgard, where Hela’s forces are attacking Heimdall and Asgard’s citizens. Banner becomes the Hulk again, fighting Fenris, while Thor and 142 battle Skurge and the resurrected warriors. Loki and the gladiators arrive to help, and the citizens board their large ship; a repentant Skurge sacrifices himself to allow their escape. Thor, facing Hela, loses an eye and then has a vision of Odin that helps him realize only Ragnarök can stop Hela. While Hela is distracted, Loki locates Surtur’s crown and places it in the Eternal Flame. Surtur is reborn and destroys Asgard, killing Hela.
Thor and the others escape with Asgard’s remaining citizens aboard the Grandmaster’s vessel. Thor, crowned king, decides to take his people to Earth. In a mid-credits scene, they come across a large spacecraft. In a post-credits scene, the Grandmaster encounters a group of his former subjects, who are still rebelling.