Barry (guest star Grant Gustin) and Iris's (guest star Candice Patton) wedding brings the gang together, but things go awry when villains from Earth-X attack the ceremony. All of the superheroes band together with help from their super friends like Citizen Cold (guest star Wentworth Miller), The Ray (guest star Russell Tovey), Felicity Smoak (guest star Emily Bett Rickards), Iris West and Alex Danvers (Chyler Leigh) to take on their most formidable villains yet. Earth's mightiest heroes - Green Arrow (guest star Stephen Amell), Supergirl (Melissa Benoist), The Flash (guest star Grant Gustin) and White Canary (guest star Caity Lotz) - lead their teams into battle to save the world.
Did You Know?
Earth-X's Snart makes an overture towards Sara, a callback to their implied relationship in Season 1, thereby also suggesting that he, like Sara, is bisexual. See more
Mr. Terrific points out that Overgirl has absorbed so much radiation that she is about to reach the Chandrasekhar Limit and go supernova. The Chandrasekhar Limit only applies when an white dwarf star reaches a mass approximately 1.4x our sun. Even if it was applicable to Overgirl, the resulting supernova explosion would have completely destroyed the earth, given the close proximity, not to mention most of the rest of the inner solar system. See more
Attention all prisoners: Great news. The cavalry has arrived.
I knew I could count on you, Pretty. Did you bring beers?
Better yet, an army.
Who needs an army when you got Legends?
The usual opening narration and title card are replaced by a special "Crisis on Earth-X" sequence. See more