home world of Svartalfheim, Bor safeguards the Aether within a stone column. Unknown to Bor, Malekith and a handful of Dark Elves escape into suspended animation. In present-day Asgard, Loki stands imprisoned for his war crimes on Earth. Meanwhile, Thor, alongside warriors Fandral, Volstagg, and Sif, repels marauders on Vanaheim, home of their comrade Hogun; it is the final battle in a war to pacify the Nine Realms following the reconstruction of the Bifröst, the "Rainbow Bridge" between realms, which had been destroyed two years earlier. The Asgardians soon learn that the Convergence, a rare alignment of the Nine Realms, is imminent; as the event approaches, portals linking the worlds appear at random. In London, astrophysicist Dr. Jane Foster and her intern Darcy Lewis travel to an abandoned factory where such portals have appeared, disrupting the laws of physics around them. Separating from the group, Foster is teleported to another world, where, beyond Heimdall's near all-seeing vision, she absorbs the Aether. Heimdall alerts Thor, leading him to Earth. When Thor finds Foster, she inadvertently releases an unearthly force, and Thor returns with her to Asgard. Odin, recognizing the Aether, warns that the Aether will not only kill Foster but that its return heralds a catastrophic prophecy. Malekith, awakened by the Aether's release, attacks Asgard. During the battle, Malekith and Algrim search for Foster, sensing that she contains the Aether. Thor's mother Frigga is fatally stabbed protecting Foster, and Malekith and Algrim are forced to flee without Foster. Despite Odin's orders not to leave Asgard, Thor reluctantly enlists the help of Loki, who knows of a secret portal to Svartalfheim, where they will use Foster to lure and confront Malekith, away from Asgard. In return, Thor promises Loki vengeance on Malekith for killing their mother. With Volstagg and Sif stalling Asgardian soldiers and Fandral assisting their escape, Thor, Loki, and Foster head to Svartalfheim. There, Loki tricks Malekith into drawing the Aether out of Foster, but Thor's attempt to destroy the exposed substance fails. Malekith merges with the Aether and leaves in his ship as Loki is impaled while killing Algrim. Thor, cradling Loki in his arms, promises to tell their father of his sacrifice. Afterward, Thor and Foster discover another portal in a nearby cave and reunite in London with Lewis and Foster's mentor Dr. Erik Selvig—who was briefly institutionalized due to the mental trauma he suffered during Loki's attack