Spoilers below for the most recent episodes of The Flash.
The Flash most recently pit the Scarlett Speedster and his heroic team against an army of sentient gorillas, setting further "anything can happen" precedents, and we're just a few weeks away from the musical crossover with Supergirl, which looks to be as baffling as anything the Arrow-verse has provided thus far. And while we knew a few details, such as the episode's villain and who was cast for "Duet," the actual subject matter has eluded fans. But now we know the episode will be putting a strong focus on one character in particular: Iris. According to co-showrunner Aaron Helbing.
Considering the whole crux of The Flash's current narrative is Barry saving Iris from a future death at Savitar's...hands?...it feels like every episode of the CW drama should have Iris super-involved in some way. One could easily assume a musical episode would be so gimmicky that the creative team would sidestep the overarching plot to deliver something more standalone and frothy, but The Flash apparently isn't going that route, which is great. I mean, assuming Iris isn't being used in some ridiculous way that has zero to do with her impending death, or lack thereof.
Especially considering Barry ended "Attack on Central City" by asking Iris to marry him, which should make everything coming up in their lives more important than everything in the past. Speaking of the past, though, set photos from the episode indicate a trip back to a time about 70 or so years ago, although without any big details given, it's hard to know what to make of that. Beyond a general hope that Jesse L. Martin owns his own jazz and blues lounge, for which he performs 24/7. I could use some singing narration from Joe.
There were hints that the episode, which will feature Glee alum Darren Criss as the classic Flash comic book villain Music Meister, would have Central City's key non-damsel in the spotlight, as shared by Aaron Helbing when talking to TVLine. One of them came from star Candice Patton herself, once production on the episode began.
A lot of familiar faces will show up during "Duet," so it'll be interesting to see how Iris factors into it all. Expect to see John Barrowman's Malcolm Merlyn and Victor Garber's Martin Stein showing up, as well as Jeremy Jordan's Winn Schott. Not to mention Melissa Benoist's Supergirl, who was kind of a gimme.
The Flash airs Tuesday nights on The CW, with the big musical extravaganza coming Tuesday, March 21, at 8:00 p.m. ET. Be sure to have your kazoos and tap shoes at the ready, and head to our midseason premiere schedule to see what else is coming to the small screen in the near future.