The crossover will start with the March 20th episode of Supergirl, entitled “Star-Crossed”:
A new villain (guest star Teri Hatcher) comes to National City, putting Supergirl on high alert. Meanwhile, Winn’s girlfriend, Lyra, gets Winn in trouble with the law. Maggie attempts to help Winn but old loyalties get in the way. The Music Meister attacks Supergirl.
The action then continues at 8PM ET on March 21st in the Flash episode titled “Duet”:
Barry and team are surprised when Mon-El and Hank Henshaw arrive on their Earth carrying a comatose Supergirl who was whammied by the Music Meister. Unable to wake her up, they turn to Team Flash to save her. However, the Music Meister surprises The Flash and puts him in a similar coma, one that Team Flash can’t cure. Kara and Barry wake up without their powers in an alternate reality where life is like a musical and the only way to escape is by following the script, complete with singing and dancing, to the end.
Finally, a teaser trailer for the crossover had been shared.
The crossover event kicks off at 8PM ET, March 20th on The CW.