'The Flash' season 3 episode 17 spoilers: Supergirl, Flash caught in Music Meister's curse

Promotional image for "The Flash"Facebook/CWtheflash

The Music Meister attacks the Flash and Supergirl in the upcoming episode of "The Flash" season 3.

Titled "Duet," next week's episode will see the highly anticipated musical Flash/Supergirl crossover. According to the official synopsis, Barry (Grant Gustin) and his team are surprised when Hank Henshaw (guest star David Harewood) and Mon-El (guest star Chris Wood) head to their Earth carrying an unconscious Kara a.k.a. Supergirl (guest star Melissa Benoist).

They later reveal that the Music Meister (guest star Darren Criss, from "Glee") was responsible for putting Supergirl under a magically induced coma. Desperate to wake her up, Mon-El and Hank turn to Team Flash to save the National City's heroine. The Music Meister eventually catches the Flash unprepared and puts him in a similar coma — one that cannot be cured by the team. Barry and Kara later wake up without their superpowers in an alternate world where life is a musical. The only way to get out is by performing, complete with dancing and singing, following the Music Meister's script until the musical is done.

The episode also serves as a mini-"Glee" reunion because Gustin and Benoist previously starred in the musical series with Criss. In a recent interview with Entertainment Weekly, Criss said he had a great time on set and he hopes he could reprise his villainous role in the future. "I certainly hope so," the actor stated. ". . . I almost don't want to say it, because I don't want to jinx it, but I want to come back. I'm not done — then I'll have my true payback!"

To give fans a bit of a tease for the upcoming episode, Gustin revealed a fun new promo image on Instagram. Barry is not wearing his Flash costume and he appears to be manipulated like a marionette. The photo also hints that things will not be all sunshine and happiness for the Central City hero in "Duet."

The third season of "The Flash" airs every Tuesday at 8 p.m. EDT on The CW.

More News in Entertainment