The heroes of Supergirl, The Flash, Arrow and DC’s Legends of Tomorrow will soon unite to defend the planet from an extraterrestrial threat in a four-part crossover episode entitled, “Invasion.” While that name may ring a bell for many of our longtime and fiercely devoted fans, it certainly won’t for everyone. In fact, it’s a good bet that thousands of the viewers who tune in for next week’s crossover will have no idea that it was inspired by a pretty big comic book event from the late 1980s. Here’s what you need to know about it…

What is Invasion?

INVASION is a three-part comic book miniseries that was first published in late 1988. It was DC’s big crossover event of the year and the first to take the guise of a Star Trek-like space opera. Keith Giffen was the driving creative force behind the story, planting seeds for it in books that he was writing at the time, including LEGION OF SUPER-HEROES and JUSTICE LEAGUE INTERNATIONAL. Giffen provided the plot and pencil breakdowns, while writer Bill Mantlo (Micronauts, The Incredible Hulk) wrote the script. Notably, much of the art in Invasion was handled by Spawn-creator Todd McFarlane, who had just finished up stints on INFINITY, INC. and DETECTIVE COMICS and after Invasion would go on to really make his name drawing Amazing Spider-Man at Marvel. Additional pencils were provided by Bart Sears, who would pencil the third and final part, and Giffen, who drew the latter half of part two.

We’re referring to Invasion as a “three part” rather than a “three issue” miniseries here because each part is much longer than a standard comic book issue. In a throwback to a format that was becoming less common, each chapter of Invasion was released as an 80-page special. In addition, the event was also spun off into a few dozen tie-in issues, touching just about every ongoing series DC was publishing at the time. These tie-in issues provided some added background and depth, but weren’t necessary to understand the core story. As such, the collected edition of Invasion only includes the three core chapters.

What is Invasion About?

Invasion introduced the Alien Alliance, a coalition of extraterrestrial races who teamed up to invade Earth to stop the existential threat posed by Earth’s super heroes. The Alliance was led by the Dominators, a fearsome looking alien race notable for the distinctive red spot on their forehead and their long, sinister teeth. Intriguingly, however, while the Dominators look and sound monstrous, they were more strategic and scientific—the brains behind the operation. It was the other races, particularly the warlike Khunds, who led the attack.

Conquering Australia and using it as a base from which they’d mount their attack, the Dominators first make Earth an offer—surrender all of the planet’s super heroes and the rest of Earth will be spared. The UN rejects the offer, formally declaring war against the invaders.

Earth’s heroes battle the Alliance, and as in all good crossovers, the fight isn’t without sacrifice. But ultimately the tide is turned with the aid of an unexpected resource. The Alien Alliance included Daxamites, thoroughly unaware that the Earth’s yellow sun would give them abilities to rival Superman’s. Eventually, after some interaction with the Man of Steel, the Daxamites switch sides, vowing to help defend the Earth and gradually tipping the battle in favor of humanity when it’s revealed how powerful they are as a force.

Meanwhile, a Dominator scientist manages to isolate the human metagene—a gene present in select humans that makes them more susceptible to gaining superpowers. He designs a Gene Bomb that causes every metahuman on Earth to lose control of their abilities, slip into a coma and eventually die. They’re ultimately saved by a small team of unaffected heroes—including Martian Manhunter, Hal Jordan, Guy Gardner and Superman—who are able to extract the information necessary to develop a cure from the Dominator’s mind.

Invasion is a surprisingly complex story that offers more to readers than just space action (though there’s plenty of that). It looks at the challenges that come with working together and the importance of overcoming them for a greater good. It asks the question of whether sacrificing a small number to save a much larger portion of the population is ever acceptable. And it features Snapper Carr forming a team of heroes called the Blasters. While a member of this team, he’d eventually hook up with and become the boyfriend of a green alien catgirl named Churljenkins. So if you’ve ever thought Snapper could benefit from some alien lovin’, well, this may just be your miniseries.

Why Does Invasion Matter?

While it’s not as seminal as DC’s Multiverse-altering events like CRISIS ON INFINITE EARTHS, ZERO HOUR or INFINITE CRISIS, Invasion was pretty massive for its time. While much of the changes it brought to the DC Universe have largely been rendered irrelevant, it did introduce one concept that remains—the metagene. The idea that there are people on Earth—metahumans—who are genetically inclined to become super heroes or super-villains is an idea that has become part of the DNA of comic books. In fact, it’s become the de facto term when referring to superhumans in-world. Characters on shows like The Flash and in movies like Suicide Squad don’t usually call super-powered characters “super heroes.” They call them metahumans.

In addition, Invasion did introduce the Dominators who have gone on to become a recurring cosmic threat in the DCU, particularly for the Legion of Super-Heroes and Green Lantern Corps.

What Else Do You Need to Know?

The upcoming CW crossover is actually the second time Invasion has served as inspiration on the small screen. The second season of Young Justice was subtitled “Invasion” and was also a loose adaptation of the miniseries, with the Dominators and the Alien Alliance replaced by the Reach.

The CW event is the first time we’ll see the Dominators brought to live action, but expect some differences between the comic and the TV adaptation. For starters, the CW heroes will only be battling the Dominators. The Alien Alliance doesn’t exist. In addition, the crossover only features the heroes from the CW’s slate of shows, while the comic featured pretty much everybody in the DCU.

That said, there are some similarities. Keep an ear out for a scaled-down variation on the Dominators’ offer to spare the planet if Earth surrenders its superhumans. There are other ties to the comic as well, but we don’t want to spoil them for you. In short, expect a fun, cosmic ride that promises to take the heroes of Arrow, Flash, Supergirl and DC’s Legends of Tomorrow to places they’ve never been before…much the same way the miniseries did back in 1988.

For more on Invasion, check out ComicPOP's discussion of the miniseries and Comics Explained history of the Dominators on the DC Fans channel.

Want to get in on the invasion? The event miniseries is available in print as a collected edition or as a digital download. Look for the CW crossover event to kick off with Supergirl on November 28th!