Barry and Iris's wedding brings the gang together, but things go awry when villains from Earth-X attack the ceremony. Oliver and the others square off against their counterparts from Earth-X and discover that they're counterparts of Oliver and Kara... and Reverse-Flash, from before his death.

Arrow discovers who Cayden's allies are, and realizes that he's badly outnumbered. However, Curtis, Rene, and Dinah have their own plans. Meanwhile, Quentin worries about getting through to Black Siren while Cayden worries about Vigilante's loyalties.