Watch Crisis on Earth-X

Crisis on Earth-X is a two-night superhero crossover event on The CW network that brings together the characters from four of their popular DC Comics-based series: Arrow, The Flash, Supergirl, and Legends of Tomorrow. The storyline centers around the wedding of Barry Allen (The Flash) and Iris West, but things go awry when a group of Nazis from an alternate Earth-X invade the ceremony. The heroes must band together to stop their evil doppelgangers and prevent them from destroying their Earth.

The event starts with an episode of Supergirl, where we see the wedding preparations and how the different characters from the four series are involved. The ceremony is held in Central City, and surprisingly, everyone from the main cast is present, except for Felicity Smoak (Arrow). However, right as the couple starts repeating their wedding vows, the celebration is interrupted by Nazi soldiers who appear out of nowhere and start attacking the guests.

The attack quickly escalates into a full-scale battle, and the heroes are forced to fight for their lives against the Nazis. However, the situation becomes even more complicated when it's revealed that the leader of the invaders is none other than the Earth-X doppelganger of Oliver Queen (Arrow), who is now the Fuhrer of the Nazi regime. This not only shocks the heroes but also reveals the existence of a whole new Earth, one that is ruled by an evil regime.

The second episode takes place on Arrow and continues the story, following the heroes as they try to stop the Nazis from accomplishing their mission of invading Earth-1 and taking it over. The heroes are not only outnumbered but also outgunned as the Nazis have powerful weapons and technology that the heroes don't have. This leads to some intense battles and some losses for the heroes.

The third episode of the crossover event is aired on The Flash, where we see the heroes trying to regroup after their initial defeat. They must come up with a new plan to stop the Nazis, and they discover that they must infiltrate the Nazis' stronghold, which is located on their Earth-X. This is easier said than done, as the Nazis have taken over Central City and are holding it under their control.

The final episode of the crossover is on Legends of Tomorrow, where the heroes successfully infiltrate the Nazis' stronghold and confront the evil Oliver Queen. This leads to a massive battle, where the heroes must fight not only their doppelgangers but also the soldiers of the Nazi regime. There are some surprising twists and turns, as well as some heartwarming moments and character development, as the heroes work together to save the day.

Crisis on Earth-X is an epic crossover event that not only brings together some of the most beloved DC Comics heroes but also introduces a new Earth and a new threat that the heroes must face. The storyline is action-packed, with some incredible fight scenes and special effects that will leave viewers on the edge of their seats. However, it also has some emotional moments and character development that give the show depth and substance. Overall, it's a must-watch for any fan of the superhero genre.

Crisis on Earth-X is a series that is currently running and has 1 seasons (4 episodes). The series first aired on November 26, 2017.