Chances are you haven’t thought a lot about Thor: The Dark World since the sequel hit theaters in 2013. The God of Thunder’s second standalone opened to mixed reviews, and though it was a success at the box office, the movie didn’t make much of a splash with fans, particularly sandwiched between Iron Man 3 and Captain America: The Winter Soldier. It’s mostly regarded as expendable, lacking the distinction of being an introductory run like the first Thor, and not as funny as its sequel, Thor: Ragnarok, without that much of a bearing on everything that’s come since.

Avengers: Endgame, however, puts The Dark World back into the conversation. There’s something impressive about the way that the film makes the seemingly inconsequential entries in the Marvel Cinematic Universe unmissable — Ant-Man and the Wasp becomes indispensable, and the plot of The Dark World is suddenly key to saving the world.

[Ed. note: spoilers for Avengers: Endgame follow.]

When it becomes clear that the only way to undo Thanos’ snap is to travel back in time and collect the Infinity Stones before they’re destroyed, the Avengers set about figuring out where (and when) they have to go. Thor has a lead on the Reality Stone: He had an early brush with red gem back in 2013 when it was in the form of the Aether, i.e. during the events of The Dark World.

Thor puts the pieces together through stream of consciousness rambling, basically recapping The Dark World for anyone who forgot exactly what happened in the movie. It’s funny, but the emotional impact that Thor’s trip back to that exact window in time suggests that the film has been criminally overlooked. The things that Thor wrestles with — his grief over his mother’s death; his largely unaddressed breakup with Jane Foster; his worry that he might not be worthy to wield Mjolnir — are all huge to his character, and were seeds planted in The Dark World. Even turning the rule of New Asgard over to Valkyrie has its roots in the second Thor film.

That Thor must prove himself worthy — to wield the hammer, to rule — is a thread that’s carried through his entire tenure in the MCU, and The Dark World acts as another test. He only returns to Earth because Jane accidentally becomes host to the Aether, and his ultimate decision not to take the throne of Asgard has everything to do with, as he realizes in Endgame, the need for him to be who he is, not necessarily who he’s expected to be. He will protect the Seven Realms, he tells Odin in The Dark World, but he “would rather be a good man than a great king.” (This should ring some bells for any Captain America devotees as a familiar theme — “not a perfect soldier, but a good man” — as well as Black Panther’s “it is hard for a good man to be a king.”)

Thor’s Endgame guilt over being unable to stop Thanos, and the further weight that places on the realization that he could actually turn back time and prevent his mother’s murder, serves as one of the film’s most poignant emotional beats. When the Aether possesses Jane Foster, the shift wakes the Dark Elves, who kill Frigga in their initial attack upon Asgard as they search for Jane. Thor is busy fighting in the dungeons when it happens, but future-Thor actually runs into his mother right before the tragedy occurs. He’s clearly tempted to change fate, but Frigga knows better. What’s important is that he knows that she loves him and, as he discovers when he tries summoning Mjolnir, that his failures do not make him unworthy.

Relevance to the larger MCU aside, The Dark World is a is worth revisiting on its own merits. The mere fact that part of it is set in high fantasy outer space immediately vaults it into fairly goofy territory. For all that it might seem a little melodramatic, it’s funny in a way that’s a natural lead-up to the bombastic quality of Ragnarok. Silence as Thor is wiped across a window, bystanders refusing to leave because they want to see the legendary hero, Chris O’Dowd (whatever happened to him, anyway?) — The Dark World is a romp.

It helps that the Dark Elves — though inconsequential to any further Marvel lore in the way that, say, Skrulls have turned out to be — are compelling villains. The dead-eyed masks they wear and the idea that they must sacrifice themselves for true firepower (on micro and macro levels, as the Kursed “berserkers” are essentially committing harakiri, and as their leader, Malekith, chooses to crash his ships to wipe out as many Asgardians as possible rather than surrender) are details that defy The Dark World’s dull reputation.

In other words, The Dark World still has emotional stakes, particularly when it comes to the fractures in Thor’s family life. Loki, now fully aware that he’s not a true Asgardian and thrown into jail by his adoptive father, has an even clearer chip on his shoulder. That doesn’t, however, mean that his years of being raised by Thor’s side amount to nothing — Thor makes it clear that he still cares about Loki, even though he can no longer trust him — nor that he doesn’t still care for Frigga. Her death profoundly affects both of her sons, reluctant as Loki may be to admit it.

The film also addresses the broader repercussions of what happens in the MCU in a way that is often overlooked in the other films. (Spider-Man: Homecoming is notable in this respect, as it offers a clear look at how the destruction caused by superheroes affects everyday people.) Jane’s personal life is thrown off by her romantic entanglement with Thor and the way his responsibilities demand his detachment, and on a more serious note, Dr. Selvig is still suffering the aftershocks of having been mind-controlled by Loki in Avengers. (Has he recovered since then? He got snapped back, right? I need answers, Kevin Feige!)

It’s good bigger-picture building in a film that can otherwise, on a surface level, seem detached from the franchise it’s a part of, though even a brief investigation proves just how essential it is.

In fairness, The Dark World came along at a time when Thor was still working towards popularity. Thor has always been a big sweetie, but it’s a perception that only really cemented itself circa Ragnarok (or, really, after Chris Hemsworth proved his comic chops in the 2016 Ghostbusters). The highfalutin aesthetic of Asgard doesn’t immediately bring to mind the kind of neon hijinks that characterized Ragnarok, a problem that Thor got around by setting the bulk of the action on Earth. The Dark World goes half and half — but makes up for it with a cogent emotional through-line and a surprising willingness to get gonzo. The film’s final sequence, which involves zapping things in and out of different dimensions, is a blast.

Now that The Dark World has properly been folded into the MCU canon rather than remaining a strange vestigial limb, it’s time to give the movie its due. It’s good as a standalone film, and as a part of a larger arc, helps to set up everything that Thor is, now.