Spoiler alert: This article does not address or reveal any plot points from Avengers: Endgame. It’s just a recommendation for a specific refresher course. Trust us on this one.

Ahead of the release of Avengers: Endgame, anti-spoiler mania has reached a point of frenzy, driven in part by the directors’ anti-spoiler statement, a seemingly actively malicious pro-spoiler movement, and an extremely popular social media hashtag urging people not to be dicks about it. The Verge is so on board that our spoiler-free review doesn’t reveal a single plot point from the movie, and neither will this post.

We’re just here to say that the film, as a whole, ties back into a whole lot of Marvel Cinematic Universe history. It’s a phenomenally referential film, and you can expect months to come of “Endgame Easter eggs you missed” posts and videos and listicles, mostly created by people who really underestimate your intelligence and your attention to detail, and hope you’ll click on yet another roundup of obvious references, out of a fear that maybe you did miss something.

We aren’t going to address what the movie does and doesn’t do with those references. We’re just going to suggest that this is the one scene from a past Marvel movie that you’ll most want to rewatch before watching Endgame. It’s one of the more celebrated sequences from 2014’s Captain America: The Winter Soldier, where Cap deals with a slowly escalating problem inside his own organization. Five-year-old spoilers ahead for Winter Soldier.

Here’s the setup: Captain America (Chris Evans) has growing reason to believe he can’t trust his own allies and employers at S.H.I.E.L.D., supposedly the organization defending Earth. Its director, Nick Fury (Samuel L. Jackson), sends Cap on what was supposedly a hostage-rescue mission, but was secretly a data-extraction mission for Black Widow (Scarlett Johansson). Later, Fury is attacked and nearly assassinated. He seeks out Cap’s help, but is shot in Cap’s apartment, whereupon Cap learns that his friendly new neighbor is a S.H.I.E.L.D. agent planted to watch him. So he’s already feeling plenty paranoid when he’s called to headquarters to debrief. And then his paranoia comes to a head when his own co-workers, who are moles for the evil organization Hydra, ambush him. They’re led by double agent Brock Rumlow (Frank Grillo), who will later become the villain Crossbones, at least long enough to kick off some key action in Captain America: Civil War.

How does this become relevant in Avengers: Endgame? We ain’t telling, except to say that you don’t need to memorize any of these details — just watch the camera and follow the action. One of the new film’s best moments works even better if you’ve seen this scene recently. You can thank us later.