There’s something missing from superhero movies.

It’s a fundamental and unique quality of the interconnected comic book superhero universe, and it’s hard to pin down in a single word. It’s not just world building, or interconnectivity, or an ever spooling timeline, but a combination of all three. It’s the idea that the superhero community is generational — that a young superhero walks into the Justice League tower for the first time and into the footprints of giants. It’s the idea that superheroes shape the world around them in big and small ways — and not just by making world governments draw up the Sokovia accords.

The best word for this concept that I’ve found is legacy. And Spider-Man: Homecoming is the first time that I’ve felt like I was seeing it in a major superhero blockbuster.

Legacy is a fundamental theme of superhero universes

The long-running, serial delivery of comic books means that there’s been plenty of time over the decades for slowing down. For slice of life, for experimentation in tone and pacing, for turning over the rocks to see what crawls out.

You get single issues about how Batman intimately affects the day-to-day lives of Gothamites, even if they’ve never met him. You get entire award-winning series about what Hawkeye does when he’s not hanging out with the Avengers. You get a whole issue just for Superman’s funeral procession, not a couple of scenes.

And you get characters who grow up, whose relationships evolve, and who pass the mantle. The successive Robins and Flashes, Superman and his family, Bucky Barnes and Sam Wilson as as Captain America, the running list of men and women who’ve served as Green Lantern of Earth — they’re all examples of beloved comic book ideas being reframed and renewed.

Inside superhero fandom and professional spaces, these are known as “legacy” characters, and they don’t just help superhero universes to stay relevant to readers over time. They also move the metaphor of empowerment at the heart of the superhero closer to the audience’s grasp. If someone who grew up worshipping my favorite superhero could eventually become that hero or work alongside that hero, maybe I could do that too.

Homecoming is superhero movie where the lead isn’t trying to live up to a personal ideal of heroism, but specific cultural one

So legacy is a sense of history, but it’s also a sense of space — narrative space. It’s the illusion of “lived-in-ness,” the idea that things happen in a setting even when the main characters aren’t around. It’s giving the reader the sense that there is a macro to this setting and a micro — they’re only seeing a part of it at any given time.

It’s not just knowing that Iron Man could meet up with Captain America in the story you’re reading — it’s feeling that they inhabit the same world, even when Iron Man is nowhere to be seen. And it’s the idea that the character you’re following now could easily pop into another one’s narrative space, no matter how different a space it is.

One of Spider-Man’s very first canonical adventures was about him trying to join the Fantastic Four. Even now, the wall-crawler has his inner-city neighborhood, he’s got whatever super-team he’s on at the moment, and sometimes he even goes to do weird science with Iron Man or weird magic with Doctor Strange. And that doesn’t make him unusual.

Superhero movies lack legacy

Baked into the idea of superheroes is that they exist alongside other superheroes, and yet it’s only within the last decade that we’ve been able to watch that happen in film. And even then, the financial constraints of actor cameos and contracts means that even the MCU superheroes still largely operate within their own tidy silos.

When they do get together, the nature of film as a medium — and the blockbuster action movie as a genre — means that their interactions are all about stakes and tension and things will never be the same. And yet, everybody’s favorite scenes from the Avengers movies are the ones where they’re just hanging out.

Legacy is also the sort of thing you can only do on a very long scale timeline in movies. Warner Bros. is desperately trying to spin up the DC Cinematic Universe, but lacks the time to have accomplished it — all of its heroes are still just meeting each other. Its history is only just beginning.

The X-Men movies could have reached this point, with characters aging out of the team and younger students taking up membership, but the nature of the film franchise so far — which has flowed to an alternate timeline to recast and hit the reset button instead of introducing new characters — has precluded it from reaching that point. (Yet, anyway. We’ll see if New Mutants can do it.)

But 16 feature length films of continuous world building (and the influence of another studio desperate to get in on the Marvel Cinematic Universe cachet) seems to have been the key for Spider-Man: Homecoming.

“I just wanted to be like you”

Much has been said about how eschewing the traditional origin story allowed Homecoming a refreshing amount of freedom, but fewer reviews focused on how allowing itself to rest heavily on Marvel’s setting enabled the movie to skip a lot of other fundamentals.

Because the background of the story’s hero and villain is so rooted in the history of the Marvel Cinematic Universe, Homecoming doesn’t have to explain what the Avengers are. It doesn’t have to establish the history of superheroes in its setting, it just has to establish that it’s fundamental to Peter’s life and move on. It doesn’t have to make up a bunch of original superhero-related incidents for Vulture to pilfer technology from. It doesn’t have to explain how Peter’s suit works, or why it has an AI assistant that allows the writers to have him plausibly and naturally explain his actions even when no other characters are around.

It doesn’t have to explain the Avengers’ past deeds, which are what make Peter want to be one of them so badly — the stakes are already there. It’s one thing to like watching superhero movies because they do impossible things. Homecoming finally gives us a superhero movie where the lead isn’t trying to live up to a personal ideal of heroism — but a very specific, fictional cultural one.

Homecoming embraces the idea that the nature of superhero universes is that they are subtly different from our own in a million ways — and that those ways make even mundane activities, like ordering a sandwich, interesting. It’s simply unlike anything else I’ve seen in superhero films up to this point.

As a long-time Batman fan, I sometimes forget that Robin hasn’t actually appeared in a live action Batman film in 20 years, despite the fact that in more than 75 years of comics history Batman has virtually never existed without Robin in some incarnation. There’s a whole layer of setting that I take from comics and map on to comic book movies that isn’t actually there, a layer that simply is not brought to the audience that just watches the films.

That audience is missing one of the most quintessential qualities of a long-running superhero stories. And now that I’ve seen how good a superhero movie can be when I’m not mentally filling in that gap — I’m going to miss it too.