Thor: The Dark World

The Dark Elf Malekith, who wants to end the universe by utilising a weapon known as the Aether, battles Bor, the father of Odin, ages ago. Bor protects the Aether inside a stone column after defeating Malekith's army, who included improved soldiers known as the Kursed, on their home world of Svartalfheim. He has no idea that Malekith, his aide Algrim, and a few other Dark Elves had vanished into suspended animation.

Loki is currently incarcerated in Asgard for his war crimes committed on Earth. The final fight in a war to settle the Nine Worlds after the restoration of Bifröst, the "Rainbow Bridge" between realms, which had been shattered two years earlier, involves Thor, together with warriors Fandral, Volstagg, and Sif repelling marauders on Vanaheim, the home of their buddy Hogun.

Darcy Lewis, the astrophysicist Dr. Jane Foster's former intern, now accompanied by her own intern, Ian, brings Jane to an abandoned factory where items have started to defy physics and vanish into thin air. Jane breaks away from the group and is taken to a different planet where she contracts the Aether.

The Nine Realms are about to join in a rare occurrence known as the Convergence, and as it draws near, portals connecting the realms start to open randomly. Thor is made aware of Jane's recent disappearance by Heimdall, prompting him to go looking for her. He brings her to Asgard after she unintentionally unleashes an unearthly energy while being detained by the police for trespassing on private property. The Asgardian healers assert that they are unable to assist her, though. Odin, who has noticed the Aether, warns that Jane will eventually die from her infection and that the Aether's reappearance signals a terrible prophecy.

The release of the Aether awakens Malekith, who transforms Algrim into a Kursed and assaults Asgard. Malekith and Algrim look for Jane during the conflict since they know she has the Aether. When they are unable to seize her, they flee, but not before slaying Frigga, the mother of Thor, in a sword battle. Thor unwillingly joins forces with Loki, who is aware of a hidden passage to Malekith's universe, in defiance of Odin's instructions not to leave Asgard. There, they plan to use Jane to entice Malekith away from Asgard so they may confront him.

In exchange, Thor assures Loki that he would be able to exact revenge on Malekith for the murder of their mother. Thor and Loki capture a Dark Elf spacecraft and flee to Svartalfheim with Jane, with Volstagg and Sif delaying Asgardian warriors and Fandral aiding their escape.

Malekith is tricked by Loki into drawing the Aether from Jane on Svartalfheim. The Aether-powered Malekith departs with his spacecraft as Loki looks to be terminally injured while defending Thor from Algrim, despite Thor's best efforts to destroy the substance. Thor pledges to inform their father of Loki's sacrifice while holding him in his arms. After Loki appears to have passed away, Thor and Jane find a new portal in a nearby cave and meet Darcy, Ian, and Jane's mentor Dr. Erik Selvig in London.

They discover that Malekith intends to unleash the Aether in Greenwich, the epicentre of the Convergence, where he will do it in order to obliterate the cosmos. Malekith and Thor engage in combat, but a portal separates them, leaving Malekith unchallenged. Thor returns in time to assist his mortal allies in transporting Malekith to Svartalfheim, where he is destroyed before he has a chance to end the cosmos.

Thor goes to Asgard and informs Odin about Loki's sacrifice before rejecting Odin's offer to ascend to the throne. Odin's appearance changes as he departs into that of a jovial Loki.

In the middle of the credits, Volstagg and Sif visit the Collector and give him the Aether, saying that it would be unsafe to have two Infinity Stones so near to each other given that the Tesseract is already in Asgard. "One down, five to go," the Collector observes as they depart. (Setting up the upcoming Guardians of the Galaxy film.)

In a post-credits sequence, Jane and Thor are reunited on Earth, but a Jotunheimian frost monster that was unintentionally brought to Earth during the decisive fight is still running wild in London.