After a pretty heavy episode, which saw Jay Garrick sacrifice himself to save Wally and also saw Barry & Iris put their relationship on hold, next week's installment will lighten up the mood a bit as Supergirl, the Martian Manhunter, and Mon-El arrive on Earth-1 after being attacked by the Music Meister.
The episode will feature a number of original compositions, which have been kept under wraps, but it's likely we'll start to get multiple sneak previews as we approach next Tuesday.
Check out the new extended promo for episode seventeen, titled "Duet," below:
Plus, here are a pair of featurettes:
"Duet" - (8:00-9:00 p.m. ET) (Content Rating TBD) (HDTV)
DARREN CRISS ("GLEE") GUEST STARS AS THE MUSIC MEISTER IN THE FLASH AND SUPERGIRL MUSICAL CROSSOVER - 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). 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. Dermott Downs directed the episode with story by Greg Berlanti & Andrew Kreisberg and teleplay by Aaron Helbing & Todd Helbing (#317). Original airdate 3/21/2017.
Blinded by anger, Barry unwittingly plays into Zoom's game and uncovers the evil speedster's true goal: to destroy all the earths in the multiverse. In the face of his life, Barry ultimately gets the upper hand against Zoom and defeats his nemesis. But unable to celebrate victory, Barry makes a world-shaking decision and speeds back in time to the night his mother died to stop Reverse Flash from killing her, irrevocably changing his past and redetermining his future.
The Flash features:
Grant Gustin as Barry Allen/Flash
Candice Patton as Iris West
Danielle Panabaker as Caitlin Snow
Carlos Valdes as Cisco Ramon
Tom Cavanagh as Dr. Harrison Wells
Jesse L. Martin as Detective Joe West
John Wesley Shipp as Henry Allen/Jay Garrick
Michelle Harrison as Nora Allen
Keiynan Lonsdale as Wally West/Kid Flash
Violett Beane as Jesse Quick
Tom Felton as Julian Dorn
The Flash returns with an all-new episode March 21