The Svartalfheim Gambit: Thor breaks Loki out of Asgard’s prisons with the help of Heimdall, Sif, and the Warriors Three. On Svartalfheim, Loki seemingly betrays Thor, slicing off his hand and handing Jane over to Malekith. However, this is an illusion. Once Malekith draws the Aether out of Jane’s body, Thor reveals his intact hand and summons Mjölnir to destroy the exposed entity. The plan partially fails because the Aether is indestructible, allowing Malekith to absorb it and escape.
Loki’s Death Fake-Out: During the battle on Svartalfheim, the Dark Elf brute Kurse impales Loki. Loki activates an implosion grenade on Kurse, killing him, but appears to die in Thor’s arms. A guard later reports Loki’s death to Odin in Asgard.
The Battle of Greenwich: Malekith travels to London, where the Nine Realms align at the center of the Convergence. Thor and Jane use scientific portal-generating rods designed by Erik Selvig to transport Malekith across dimensions. Thor uses his hammer to strike the rods through Malekith, teleporting the Dark Elf back to Svartalfheim, where his falling ship crushes him.
The Ending Twist: Thor returns to Asgard and tells Odin he cannot accept the crown, choosing instead to live on Earth with Jane. Odin respects his choice and bids him farewell. As Thor exits, "Odin" transforms, revealing himself to be Loki, who faked his death on Svartalfheim, deposed/displaced the real Odin, and seized control of Asgard disguised as the Allfather.