The Supergirl/The Flash musical cross-over finally arrives with season three’s episode 17 airing March 21, 2017. Supergirl (Melissa Benoist) and her friends turn to Barry and Team Flash for help when the Music Meister (Glee‘s Darren Criss) attacks Kara. Dermott Downs directed the episode from a script by Aaron Helbing and Todd Helbing (story by Greg Berlanti and Andrew Kreisberg).
The season three cast includes Grant Gustin as Barry Allen/The Flash, Tom Cavanagh as Harrison Wells, Danielle Panabaker as Caitlin Snow, Carlos Valdes as Cisco, Jesse L Martin as Joe West, Keiynan Lonsdale as Wally West, and Tom Felton as Julian.
The ‘Duet’ Plot: DARREN CRISS GUEST STARS AS THE MUSIC MEISTER IN THE FLASH AND SUPERGIRL MUSICAL CROSSOVER – Barry (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 (Benoist) who was whammied by the Music Meister (Criss). 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.