Barry (Grant Gustin) and team are surprised when Mon- El (guest star Chris Wood) and Hank Henshaw (guest star David Harewood) arrive on their Earth carrying a comatose Supergirl (guest star Melissa Benoist) who was whammied by the Music Meister (guest star Darren Criss).
However, the Music Meister surprises The Flash and puts him in a similar coma, one that Team Flash can’t cure.
Unable to wake her up, they turn to Team Flash to save her.
The two-night event will get started with Supergirl on March 20, and crescendo in the following night’s Flash “Duet.”