Thor: The Dark WorldSave

Pre-history. Long before the founding of Asgard's recorded civilization, the Nine Realms aligned in a cosmic event called the Convergence — a once-every-five-thousand-years gravitational anomaly when all nine planetary realms occupy the same line in space-time and dimensional barriers between them collapse. During the previous Convergence, the Dark Elves of Svartalfheim — a pre-creation species who existed before the universe's birth, an army of pale-eyed, white-faced humanoid invaders — attempted to weaponize an ancient liquid-pre-cosmos substance called the Aether. The Aether is one of the six Infinity Stones in liquid form, the Reality Stone manifested as a sentient red-orange fluid. Malekith (Christopher Eccleston, the Ninth Doctor in heavy prosthetic makeup), the Dark Elves' commander, planned to use the Aether to plunge the universe back into the pre-cosmic darkness from which the Dark Elves originally came. Bor — Odin's father — led the Asgardian armies against Malekith at the Battle of Svartalfheim. The Asgardians won. Malekith escaped with a handful of soldiers, including his lieutenant Algrim, into suspended animation aboard a hidden Dark Elves vessel. Bor sealed the Aether in a stone reliquary and hid it in a pocket dimension. He left this to his son Odin's stewardship. The Asgardians have been waiting for the next Convergence ever since.

Present day. Asgard. Loki — Tom Hiddleston, in chains, in a gold prison cell — has been brought back from his New York rampage in The Avengers (2012) for trial. Odin (Anthony Hopkins) sentences him to permanent imprisonment in Asgard's deepest dungeons. Loki, who had been planning some next betrayal, has been outmaneuvered. He's locked in a holographic-glass cell along with other Asgardian criminals. Frigga (Rene Russo), Loki's adoptive mother, has been the only Asgardian visiting him during his imprisonment. She brings him books. She tells him to remain hopeful. Thor, meanwhile, has spent the two years since the Battle of New York consolidating Asgard's military power across the Nine Realms — defeating renegade kingdoms, pacifying border-realm warlords. Thor and Sif have been growing apart. Thor has been pining for Jane Foster on Earth and hasn't visited her since the events of Thor (2011).

London. Jane Foster (Natalie Portman) is in London on assignment with her partner Dr. Erik Selvig (Stellan Skarsgård) and intern Darcy Lewis (Kat Dennings). Selvig, post-Avengers, has been working with the New Asgard astrophysics division at a former Royal Naval Yard. He has been investigating residual portal disturbances from the New York Battle's aftermath. Jane is dating an Englishman in London. She's been on six dates with a slightly-too-perfect-for-her-taste medical doctor named Richard, who Darcy thinks is great. Then Darcy notices a small device in a London warehouse that has been registering bizarre gravity readings. Jane investigates with Darcy. They walk into the warehouse and find a small dimensional aperture — a Convergence-aligned portal — that has been opening and closing in the empty warehouse for two days. Jane steps into the portal.

The Aether infection. Inside the dimensional pocket Jane has stumbled into is the small stone reliquary containing the Aether — Bor had hidden the Aether here ten millennia ago. Jane touches the reliquary. The Aether activates. It senses a biological host. It seeps through the stone into Jane's body. She has been infected with the Reality Stone in liquid form. The Aether bonds with her cellular structure. She passes out in the pocket dimension and is sucked back into the London warehouse moments later. Thor — alerted by Heimdall's all-seeing watchman station in Asgard — Bifrost-jumps to London and finds Jane unconscious in the warehouse. He brings her to Asgard via the Bifrost for treatment.

Odin diagnoses the Aether. He's seen it before. He recognizes the symptoms in Jane immediately. The Aether is killing her from the inside out. The infection is irreversible. The only way to extract the Aether is to wait for it to weaken from saturation — which would happen only after Jane dies and the Aether's host bond breaks. Frigga, examining Jane, identifies that the Aether has connected its dimensional homing-beacon to Malekith — the Dark Elves can now find Jane. The Convergence is in eight days. The dimensional barriers are weakening. Malekith's vessel — drifting in suspended animation for ten millennia — is detecting the Aether's reactivation. He's waking up.

Malekith attacks Asgard. The Dark Elves vessel materializes in Asgard's airspace on the eve of the next Convergence and launches a full-scale invasion of the Asgardian capital city. The attack is the most-coordinated military assault Asgard has faced in five thousand years. The Dark Elves use Reality-Stone-fueled black-hole-grenade weaponry and atmospheric stealth-cloaks. They breach the city's gold-domed citadel through the palace's western flank. Frigga, who has hidden Jane in Loki's old bedroom for safety, holds off Algrim — Malekith's lieutenant transformed by the Aether into a giant, near-immortal Kursed warrior — with her own swordwork in the palace corridors. She buys Jane minutes to escape. Algrim runs her through with a Dark Elves blade. Frigga dies in the palace corridor. Malekith retrieves the Aether-host (Jane) — but Thor arrives, fires Mjolnir at Malekith mid-extraction, and Malekith is forced to retreat with only minor Aether-leakage from Jane's body. Malekith escapes back to the Dark Elves vessel. The funeral begins.

Frigga's funeral. The Asgardian funeral rite is one of the most-quoted images in MCU iconography — Frigga's body is placed on a Viking longship at the dock of the Asgardian capital and the entire royal family stands on the shore. Hundreds of similar small Viking boats containing the bodies of fallen Asgardian soldiers light themselves and drift out into the cosmic river that flows around the capital, all carrying their lit pyres into the sea. Heimdall raises his sword and lights the final beacon. The boats burn in starlit darkness. Loki, in his prison cell, watches the ceremony through a small window. He drops to his knees. He sobs. The most-redemptive moment of his arc.

Loki recruited. Thor visits Loki in his cell at sunrise the next morning. Frigga had been Loki's last and only emotional anchor. Loki, finally broken, agrees to help Thor against Malekith — partly to avenge their mother's death and partly because there's nothing else left for him. Thor breaks Loki out of his cell. They escape Asgard via a secret pre-Bifrost portal Loki has known about for centuries. They steal a Dark Elves cargo vessel from Asgard's exterior loading docks. They fly through the Convergence's dimensional gaps to find Malekith on Svartalfheim. Jane Foster goes with them. The plan: lure Malekith into pulling the Aether out of Jane (which would normally kill her), then attack with Mjolnir at the exposed moment.

The Svartalfheim plot. Malekith's Dark Elves landing site on Svartalfheim — the home planet of the species. Volstagg and Sif, in Asgard, are running cover for Thor's escape. Loki, in front of Malekith, theatrically delivers Thor to Malekith as a bound prisoner — claiming he's defected back to villain status. Malekith, suspicious but eager, extracts the Aether out of Jane's body via a Dark Elves channeling array. The Aether emerges as a red-orange viscous river of energy hovering in midair between Malekith and Jane. Thor breaks his bonds (Loki had not actually bound him), summons Mjolnir, and tries to destroy the Aether with Mjolnir's lightning while it's exposed and disconnected from a host. The lightning strikes the Aether. The Aether absorbs the lightning. It does not destroy. It re-bonds, this time directly with Malekith — who is now the next host. He is amplified by the Reality Stone's full power.

Loki's apparent death. Algrim/Kurse — Malekith's giant lieutenant — attacks Thor. Loki gets between them. Algrim impales Loki with a Dark Elves Black Hole grenade detonator and the explosion knocks both Algrim and Loki off the cliff. Loki dies in Thor's arms, smiling, finally redeemed. "I'm sorry. I'm not. I am." Thor leaves Loki's body on Svartalfheim and grabs Jane and escapes through a dimensional portal back to Earth. The Convergence has begun. Malekith — fully Aether-charged — is heading to Greenwich, England, at the heart of the Convergence's epicenter. He plans to use the Convergence to channel the Aether's full power across all Nine Realms simultaneously and reset the entire cosmos to pre-creation darkness.

Greenwich. The film's climax in central London. The Convergence has fully aligned. Dimensional portals are randomly opening throughout the Greenwich district — to the Asgardian throne room, to a Svartalfheim battlefield, to a Niflheim ice plain, to a primordial molten realm, to the Quantum Realm. Cars and birds are falling through space-bending portals into other realms. The dimensional barriers are paper-thin. Malekith arrives at the Greenwich Royal Observatory with the Aether glowing throughout his body. Thor engages him in personal combat. They tear through dimensional rifts mid-fight — at one point Thor punches Malekith into a portal that drops him onto a desert in Jotunheim, then a different portal drops them both onto a Niflheim ice plain. The fight crosses three realms in five minutes.

Erik Selvig saves the day. Jane and Darcy have set up an array of gravimetric inverters around the Royal Observatory. Selvig, having spent the previous year in mental-illness recovery after Loki's possession in Avengers, has been working through his recovery by inventing portable dimensional barrier control technology. The team places the inverters at four points around the Observatory grounds and switches them on. The inverters force-collapse the dimensional portals around the Aether at Malekith's exact location. Malekith and the Aether disappear into a Svartalfheim portal at the precise moment Thor lands a Mjolnir-strike on the Aether. The explosion blasts Malekith back into his own homeworld. Malekith's spaceship crashes onto him from above and crushes him. He dies on Svartalfheim. The Aether is destroyed — or rather, dissipated into pure energy that re-condenses into its Reality Stone solid form in the wreckage.

Aftermath. Thor returns to Asgard. He's been offered the throne — Odin is preparing to step down as the Aether crisis has aged him. Thor declines. "I cannot be king while my heart is here on Earth." He gives Odin the news that Loki died protecting him. Odin nods grimly. Thor walks out of the throne room and Bifrosts back to Earth.

Odin's not Odin. The camera holds on Odin's face on the throne. Odin's face shimmers. It dissolves to Loki's face. Loki is on the throne, in Odin's robes, smiling. Loki had faked his own death on Svartalfheim using a Dark Elves illusion-enchantment and Algrim's body. He has imprisoned the real Odin somewhere off-screen on Earth (revealed later in Thor: Ragnarok (2017)'s Doctor Strange opening) and assumed his identity on Asgard's throne. Loki is now ruling Asgard. He's been undetected for the past three weeks because Odin's family is not paying attention. The audience knows. Thor doesn't.

Mid-credits. Volstagg and Sif have flown the Aether — re-condensed into its solid Reality Stone form — to the planet Knowhere in the Tivan System. They deliver it for safe-keeping to the Collector — Benicio del Toro, the silver-haired curator of the universe's largest private collection of artifacts. Volstagg explains that with the Tesseract (the Space Stone) already kept in Asgard's vault, having two Infinity Stones in one location would be too dangerous. The Collector accepts the Aether. As Sif and Volstagg leave, the Collector picks up the reliquary and turns to a hidden camera. "One down. Five to go." The first hint that the Collector — and someone behind him — is building a collection of all six Infinity Stones. Cut to credits. The Infinity Saga's roadmap is officially live.