In 2988 B.C., the Dark Elves attempted to wipe out the Nine Realms during the Convergence through use of the Aether. Bor, the then-king of the Asgardians, learned of the Dark Elves' intents and confronted them on their homeworld, Svartalfheim. A titanic battle ensued, during which the Aether was taken by the Asgardians and the Dark Elf leader, Malekith, fled with his lieutenant Algrim and various other survivors into suspended animation. They would then wait out the next 5,000 years until the Convergence would begin again and the Aether would reveal itself.
In 2013, Jane Foster accidentally stumbled upon the Aether after being sucked through a portal from the Convergence, and become its unwilling host. Foster unintentionally lured Malekith to Asgard, who infiltrated his lieutenant Algrim to transform into Kurse and allow a sacking of the realm by the Dark Elves in their search for the Aether.
Realizing the Dark Elves' strength, Thor orchestrated a plan to lure them away from Asgard and into a confrontation on Svartalfheim, whereas he would be able to kill Malekith and destroy the Aether. He did this by freeing his war criminal brother, Loki, who helped Thor in getting Foster away from Asgard and to Svartalfheim. Sensing this, Malekith and his ilk pursued them there.
The two parties met each other on the war ridden surface of the planet, where, in an unexpected turn of events, Loki appeared to betray Thor and hand Jane Foster over to Malekith willingly. As Malekith extracted the Aether from Foster's body, Loki's betrayal was revealed to be a ruse. Thor quickly regained Mjølnir and used it to attack the Aether and blow it to pieces, only for it to reconstitute itself, as it was indestructible. Malekith then absorbed the Aether, and left the planet.
Kurse and a small platoon of Dark Elves stayed behind to battle with Thor and Loki. While Loki dueled with the soldiers, Thor brawled with Kurse, who had been drastically empowered by a Kursed Stone and was easily able to overpower Thor. Brutally beaten, Thor was nearly killed by Kurse before Loki intervened and stabbed Kurse through the chest. This did little to deter the Dark Elf, who took the blade and stabbed it through Loki's solar plexus. Fortunately, Loki was able to snatch a Black Hole Grenade from Kurse as he was being stabbed, and set it off. Kurse was subsequently killed.
Loki appeared to die from the injury, and Thor and Foster were left alone to find a way off the planet.
While Loki appeared to have died in the battle, it was not the end of him. Faking his death, Loki took the guise of an Einherjar Guard and made his way back to Asgard, where he placed a spell on Odin, causing the Allfather to lose his memories and stripping him of his immense power. Loki then transported himself and Odin to New York City, leaving his adoptive father outside of a nursing home. Loki then returned to Asgard, using his magic to disguise himself as Odin and usurp the throne, which he would have for the next four years, until Thor found out about the deception from Surtur, and forced Loki to drop the act when he returned to Asgard.
Thor and Jane Foster, meanwhile, took refuge in a cave, where they discovered a portal left by the Convergence that led them to Earth. They would eventually confront Malekith at Greenwich, where Thor would battle and kill Malekith, ending the Second Dark Elf Conflict.