“Thor: Ragnarok” is hitting theaters this weekend, but it’s been a while since Thor led his own movie. “Thor: The Dark World” came out four years ago, and fans will want to remember what happened last time Thor and Loki were together.

Thousands of years ago, a Dark Elf called Malekith (Christopher Eccleston) had used something called the Aether and nearly destroyed the Nine Realms. The Asgardians stopped him and hid the Aether away (the Aether appears to be red liquid, but it’s actually an Infinity Stone). Malekith and the Dark Elves managed to stay in suspended animation and, as all villains do, he vowed to get his revenge one day.

In the present day, Loki (Tom Hiddleston) is in big trouble after leading the attack on New York in “The Avengers.” Odin (Anthony Hopkins) gives him a life-sentence.

On Earth, Jane Foster (Natalie Portman) has found portals and tries to study them. She gets swallowed by one and is somehow infected by the Aether. Thor (Chris Hemsworth) arrives shortly afterward (because he’s been having Heimdall keep tabs on Jane) and takes her to Asgard.

what happened in Thor The Dark World
Thor decided to go against Odin's rules to save Jane in “Thor: The Dark World.” Marvel

Odin immediately recognizes that the Aether is in Jane, and he knows they’re in trouble. Odin disapproves of Jane’s presence, but his wife Frigga (Rene Russo) bonds with her son’s love interest. Unfortunately, the Aether’s presence triggers the Dark Elves, waking them up from suspended animation. They attack the palace and kill Frigga.

Odin imprisons Jane, but Thor knows that makes her a sitting duck for Malekith. Although it’s treason, Thor frees Jane and Loki, who knows of secret portals that could be used to get Jane out of Asgard. Loki and Thor pilot a Dark Elf ship to save Jane and lead Malekith away from Asgard.

Loki brings Thor and Jane through a portal that goes straight to the Dark Elves’ homeworld. The Aether is taking over Jane’s body, and Loki seems to be ready to betray his brother. Malekith finds them quickly and Loki cuts off Thors’s hand and says Malekith can have Jane. He just wants a front seat to Asgard’s destruction. Malekith drains the Aether out of Jane’s body, but Loki didn’t actually betray his brother. This was the plan.

Thor: The Dark World
Loki and Thor teamed up in “Thor: The Dark World,” and they will work together again in “Thor: Ragnarok.” Marvel

Thor’s severed hand was a trick. The God of Thunder tries to use Mjølnir to destroy the Aether, which is now a red stone, but it’s indestructible. Malekith’s warrior Kurse (Adewale Akinnuoye-Agbaje) fights Thor, and Loki tries to help. He manages to destroy Kurse, but he gets impaled with his own sword in the process. Loki apologizes to Thor for his crimes, and it looks like he dies in his brother’s arms.

Thor and Jane head back to England, where they learn that Malekith has been setting up portals all over the planet. He plans to spread the Aether through the portals to bring the apocalypse. When portals open above Greenwich, Thor and Malekith engage in a big battle. Realizing the Aether can’t be destroyed, Thor impales Malekith instead. The villain is later killed when his damaged Ark is teleported back to his planet and lands on top of him.

Malekith
Malekith was the villain after an Infinity Stone in “Thor: The Dark World.” Marvel

Thor goes home and Odin says he is proud and his son will be a good king. Thor says he isn’t ready to be king yet and goes back to Earth to be with Jane. After he leaves, Odin is revealed to be Loki. He has taken his father’s place and has been ruling Asgard ever since.

In the post-credits scene, the Aether is brought to The Collector (Benicio Del Toro), also known as Taneleer Tivan. The Asgardians tell him that they already have the Tesseract in their vault and keeping two Infinity Stones in the same place would be too dangerous. The Collector is thrilled to take it off their hands, and after they leave, he says that he only has five more to go.

Of course, “Thor: The Dark World” wasn’t Thor’s last appearance. He was also in “Avengers: Age of Ultron.” Thor had a vision about the Infinity Stones, and at the end of the movie, he said he was leaving to learn more about them.

In “Thor: Ragnarok,” which is receiving stellar reviews, the God of Thunder will quickly discover that Loki has been impersonating Odin, and their father has been sent to live on Earth. As seen in the post-credits of “Doctor Strange,” the sorcerer (Benedict Cumberbatch) agrees to help Thor find his father as quickly as possible so Loki doesn’t stay on Earth too long. Their adventure quickly gets complicated when Hela (Cate Blanchett), the goddess of death, is freed from her prison.

“Thor: Ragnarok” hits theaters Friday.