This year's biggest DC television series crossover is finally happening on The CW. The highly anticipated four-way crossover event will begin on “Supergirl” Season 3, Episode 8 and “Arrow” Season 6, Episode 8 on November 27, and conclude on “The Flash” Season 4, Episode 8 and “Legends of Tomorrow” Season 3, Episode 8, which are scheduled to air on November 28.

The CW has been teasing the four-way crossover with trailers that revealed some of the things that fans should look forward to. This isn’t the first time The CW is having a crossover, but this one is special because, aside from gathering the biggest silver screen heroes, the shows will be introducing supervillains from an entirely different dimension.

So, before the first episode airs, here’s a quick recap of what’s mainly going to take place in the four-episode crossover.

Barry and Iris to finally tie the knot

As revealed in the teasers, the main DC heroes will be reuniting for Barry Allen and Iris West’s wedding. Aside from Oliver Queen, Kara Denvers, and Sara Lance, most of their crew members will also be present at the joyous event.

However, just when the wedding ceremony is about to reach its climax, they get interrupted by a group of soldiers clad in black armor. However, these soldiers turn out to be Nazis, and Supergirl, Arrow, White Canary, The Flash, and more of the invited guests have to step in and postpone the merry celebration to save the world from the unexpected invasion.

Understanding ‘Crisis on Earth-X’

As revealed in the previews, the Nazis are being led by powerful supreme leaders.

However, these leaders turn out to be the evil counterparts of the DC shows' superheroes. Crisis on Earth-X is the fourth yearly Arrowverse crossover, and it will feature a clash between superheroes and supervillains.

The hostile visitors come from the 53rd Earth called Earth-X, and this Earth has a different timeline where the Nazis won the war, and successfully took over the world. Aside from the radical government's strengthened forces, the villains from Earth-X are also set to unleash their doomsday superweapon on Earth. Supergirl, Flash, White Canary, and Green Arrow reunite with other heroes to put a stop to the enemies' evil plans.

Earth-X leaders too strong?

The CW has already promised fans that the crossover event will be filled with action, and that it will be more emotional than the “Invasion” crossover. In addition, fans will be treated to rare scenes where Supergirl and the rest of the superheroes are subdued by the villains, because they’re as powerful as them.

One of the trailers teased Supergirl/Kara unconscious, and it seems like she just took a devastating blow. This might be a hint as to why Supergirl isn't with the team most of the time. The teasers also revealed that the superheroes will be captured by the enemies, and it seems like it’s up to the sidekicks to help them.