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?
Maisie Richardson-Sellers accidentally slips into her native English accent aboard the Nazi Waverider, when she says "...but we don't know what we're looking for!". See more
[asking John to marry him and Felicity
Uh, John, what do you say?
You kidding me, Oliver? I'm the guy for the past six years that's been trying to keep you two together. It's only fitting that I marry you.
The usual opening narration and title card are replaced by a special "Crisis on Earth-X" sequence. See more