Captain America: Civil War released its trailer last week, and it’s coming in six months. This is a big, record-breaking deal — the first time a movie in the Marvel Cinematic Universe is built on the heroes fighting each other, instead of villains. It’s also based on arguably the biggest Marvel comics crossover event. So if you — someone who’s watched The Avengers and much of the other Marvel Cinematic Universe — have questions, I’m here as someone who’s read most of the related comics to answer them.

So what is “Civil War”?

In business terms, it’s simple: every year since 2004, Marvel has done a major Avengers-based event, pulling in as many relevant characters as they can. “Civil War” was 2006’s event, and arguably the biggest and most ambitious of any of them. For better or for worse, it defined the 2004-2012 Marvel comics universe.

Got it. What’s the story of “Civil War”?

In-universe, it starts like this: a superhero/villain battle, broadcast on television, ends up killing hundreds of civilians, including an elementary school. This pushed the government to attempt to register and unmask all costumed vigilantes, dividing the superhero community.

Captain America wants superheroes to be free and able to act without government restriction. Iron Man wants superheroes to be registered by the government, trained, and regulated. Most importantly, heroes would have to register their secret identities with the government.

Then they fight about it!

In theory, this is great. Marvel has a long tradition of the “team-up” where two characters mistakenly fight one another before turning on the “real” villain together. But there’s no team-up here. Just irreconcilable philosophical and practical differences between heroes.

Unfortunately, the story the comics actually told was actually far more muddled. Yes, Captain America is against registration, but that’s only really because the government attacks him before doing anything else. And Iron Man is opposed to registration initially, decides to support it as the least worst option, then suddenly turns full fascist.

So what went wrong?

Marvel hired the wrong writer for the main “Civil War” series. Mark Millar was fresh off his run on “The Ultimates” — a wildly popular alternate-universe Avengers. Those characters engaged directly with politics, squabbled constantly, and had a story constant violent forward momentum, which seems like a good fit.

The problem was with tone. Millar tends to write with a nasty, semi-satirical, comedic nihilism, while throwing political concepts at the wall to see what sticks. “Civil War” should have been the great tragedy of the Marvel universe, instead it was an incoherent slap-fight.

Yet despite all that, Civil War isn’t all bad. Millar’s main series has problems, but the side stories—

Hold up, side stories? How is this thing structured?

Every modern Avengers event has the same structure. There is a main series of 6-10 issues, which is the heart of the story. Then there are a bunch of side stories — like, 100 issues of them in this case — that come in two forms. Some are invented just for the event, like “Civil War: Front Line” which follows a pair of newspaper reporters as they document the event. Others are a few issues of long-running series, like Amazing Spider-Man.

(All of the Avengers crossovers are structured in this way, which has a tendency to make them relatively easy for readers to dip into, but rarely above average quality. As a comparison, X-Men crossovers are more tightly-serialized 10-15 issue stories, and much better for it…if annoying to buy.)

And these were good?

Yes! Four in particular stand out. J. Michael Straczynski took the role of writing about the Superhero Civil War with gusto, writing it as the philosophical and personal tragedy that it should have been in his Amazing Spider-Man and Fantastic Four (the latter of which was effectively taken over by Dwayne McDuffie halfway through).

The cover of New Avengers #23, the fantastic Spider-Woman "Civil War" story.

The lead Avengers comic of the time, New Avengers, turns into an issue-by-issue examination of why its major characters ended up on the side they did. It’s slow, beautiful, introspective, and fantastic. Finally, the aforementioned “Front Line” did a great job of coming at the idea of Civil War from a new perspective, although it struggles a bit with overselling the gravitas of the actual story.

You said that “Civil War” was Marvel’s biggest event of the 2000s. What did you mean?

Well, first there’s the size: it’s roughly 100 issues of main story and tie-ins. It was also advertised like you wouldn’t believe, with “Whose Side Are You On?” slapped onto anything Marvel-adjacent.

More importantly, “Civil War” was the centerpiece of Marvel’s new strategy as they rebuilt after their bankruptcy in the 1990s, which led into their current cross-media corporate dominance. In the early 2000s, Marvel scored a few huge hits with slick, cinematic-looking reboots that largely shoved aside complicated continuity: the Ultimate universe, led by writers like Brian Michael Bendis and Mark Millar, took the core elements of Spider-Man, the Avengers, and the X-Men, and modernized team to huge acclaim. Meanwhile, New X-Men successfully cleared away most continuity and built a simple, core mutant team within the main Marvel universe.

So Marvel set about doing this with most of their characters. Ed Brubaker was given the reins of Captain America in 2004, and his “Winter Soldier” arc revitalized Cap based on his oldest mythology. Warren Ellis, in a six-issue run of Iron Man called “Extremist,” took the Golden Avenger, boiled him down to his core elements, and broke him even more after that.

Iron Man: Extremis

In 2004, Bendis was handed the keys to the Avengers with the “Avengers Disassembled” storyline, which got rid of several core team members like Vision, She-Hulk, Hawkeye, Ant-Man, and Scarlet Witch. His “New Avengers” consisted of mainstays Captain America and Iron Man, alongside popular anti-authoritarian heroes, like Spider-Man, Wolverine, and Luke Cage. He also helped reform the excellent Spider-Woman, turning her into a core hero, with Carol Danvers (Ms. Marvel/Captain Marvel) swiftly following.

The Avengers also got a major crossover event every year from 2004 on. For the first several years, they told an epic story in four parts:

The New Avengers come together, (2004-2006)

“Civil War” splits the heroes (2006-2008)

The “Secret Invasion” defeats the heroes, villains take over (2008-2010)

Villains defeated, return to “Heroic Age” status quo (2010-2011)

“Civil War” is the most essential of these because it most directly disrupts the idea that all the heroes are good and on the same side. It also more than demonstrated the sales viability of the massive crossover event.

All right, let’s get down to brass tacks here.

I love brass tacks!

First things first: I’ve got Marvel Unlimited or access to all of these comics. What should I read for the full “Civil War” experience?

I’ve mentioned most of them, but here’s the main list:

To prepare:

“Secret War”, a 2004 mini-series explaining why Nick Fury isn’t running S.H.I.E.L.D. anymore, and general governmental distrust.

“New Avengers” from the beginning.

“Captain America” (2004) from the beginning doesn’t directly work into “Civil War” but it reframes the character, introduces the Winter Soldier, and is amazing.

“Extremis”, the six-issue Iron Man arc

The necessary issues:

The main “Civil War” series

“Civil War: Front Line”

Amazing Spider-Man #532-538

Fantastic Four #538-541

“Civil War: The Confession”

And the aftermath:

Continue Brubaker’s Captain America.

Warren Ellis’ Thunderbolts is the most essential post-“Civil War” book, laying the groundwork for how the villains took over in the aftermath. It’s also one the best superhero comics I’ve ever read.

A toy commercial from Warren Ellis' 'Thunderbolts'. Straight-up villains like Venom and Moonstone defeating the "terrorist" Captain America

New Avengers continues the story of the anti-Registration forces.

Mighty Avengers starts the story of the pro-Registration forces — although both of these are weaker than New Avengers was before “Civil War”.

Onto the story itself! Whose side was everybody on?

The pro-registration forces were led by Tony Stark, Reed Richards of the Fantastic Four, and Hank Pym, the original Ant-Man, in his unstable Yellowjacket persona. These were arguably the three greatest scientist-heroes of the Marvel universe, and worked under the technocratic assumption that the science said this had to be done to stop further disasters.

They were supported by Ms. Marvel (who would become Captain Marvel, soon to have her own film), Black Widow, War Machine, and more. And Maria Hill and the entirety of S.H.I.E.L.D. were in charge of implementing the government’s plan.

The anti registration forces were led by Captain America, Luke Cage, and Falcon (with the most prominent black heroes fighting on the side of civil rights). They were aided by the Invisible Woman (going up against her husband, Reed Richards), the Human Torch, the Punisher, and Daredevil. The group is later joined by Black Panther and Storm, just-married. Jessica Jones was with Luke Cage, though not an active combatant.

Many were caught in the middle. Spider-Man is the protagonist of the series, initially siding with Iron Man, revealing his secret identity, and then switching sides when he realizes how far Tony’s gone. The Thing watches his team split up, and decides to just bail. The X-Men declare themselves neutral and deal with their own problems, as they’ve recently lost almost every mutant in the world. Amusingly, Jennifer Walters opposes registration as a lawyer, but in her superhero form as She-Hulk, she supports it.

Right, I’ve seen every Marvel movie and TV show, there are a lot of heroes I know of that you’re not mentioning here! WHERE THE HELL IS THOR?

This is true: the density of the Marvel comics universe means it had a cast of hundreds, while there are only a couple dozen heroes in the MCU, so the omissions are glaring.

Thor is by far the biggest one — he died alongside the rest of the Norse gods in the Ragnarok event at the same time as “Avengers Disassembled.” It’s strongly implied that had he been alive, his simple personal morality would have split the difference between Tony and Steve’s idealism and stopped the conflict from escalating.

Likewise, Nick Fury is in hiding after he overstepped his bounds in the War on Terror metaphor “Secret War”. His successor at S.H.I.E.L.D., Maria Hill, just doesn’t have the clout or experience at this point to stop the situation from escalating.

Scarlet Witch, Hawkeye, original Vision, and Scott Lang’s Ant-Man are all out of the universe following “Avengers Disassembled”, although all return fairly soon. Quicksilver was largely adjacent to X-Men stories in this era.

Bucky Barnes is nowhere near the center of events as in the film trailer, but is still in hiding after recovering from his mental conditioning. He joins up with the anti-Registration Avengers soon after, though.

Hulk was fired into space by many of the pro-Registration heroes, and at the time, was merrily engaging in the “Planet Hulk” event. Which was awesome.

The Guardians of the Galaxy as we know them weren’t a team yet, but most of them were engaging in the “Annihilation” event at the same time, in which Marvel destroyed and rebuilt its cosmic setting. “Annihilation” is also awesome.

All right, let’s get into spoilers. What’s the biggest deal? Can I expect it in the film?

The big ending plot point is this: Captain America, realizing that the Superhero Civil War is hurting innocent civilians, immediately surrenders. As he is heading into the courthouse soon after, he’s shot and killed by a villainous sniper. Soon after, Bucky Barnes picks up the shield and becomes the new Cap.

Will this happen in the film? That’s a tougher question. Both Chris Evans and Robert Downey, Jr. have made noises about being unhappy with their Marvel contracts in the past, and this is the perfect point for either to get out of it. Evans makes more sense than Downey in that it’s Captain America’s film, he’s not as essential an actor as Downey is to the MCU, and he has a ready-made, canonical replacement in Sebastian Stan’s Bucky. Yet Iron Man dying would be an awfully appealing twist for Marvel to attempt, turning audience expectations on their heads.

You mentioned that Iron Man goes full fascist. How so?

The two biggest problems: he (and Reed Richards) create superhero-proof prison in the Negative Zone, a nasty alternate dimension. And they just chuck every hero or villain they capture into what is basically sci-fi Guantanamo Bay.

The two scientists also note that with Thor missing, they could use his power…so they clone him. The clone Thor utterly lacks the real Thor’s morality, and, like a stereotypical rampaging policeman promptly murders the anti-Registration hero Black Goliath as soon as he steps out of line. It’s hard to see anything this irredeemable happening in the film, especially given how safe the MCU tends to play, well, everything…but we can hope.