Supergirl - Prom Night!

"Prom Night!" leaves Supergirl (Melissa Benoist, who doesn't appear in this episode) trapped in the Phantom Zone in favor of a whacky time-travel episode as Nia (Nicole Maines) and Brainy (Jesse Rath) travel back to the 90s looking to secure a biological sample from Kara's past in hopes of using it to find her in the the Phantom Zone. So quickly following The Flash's recent 90s time-travel episode doesn't help the premise, nor does the sitcom-ish humor stretched to an hour's lenghth, but it does allow the show to bring back the younger actresses for Kara (Izabela Vidovic) and Alex (Olivia Nikkanen) one more time. As expected, the pair's mission goes wrong leading to them interacting with Kara and Alex and accidentally changing past events causing unknown repercussions as the episode comes to an end with the two time travelers captured by aliens who were originally caught by the DEO.

The abscene of the show's star is certainly felt, as this marks the first episode in which Benoist doesn't appear, even more so with so few of the regular supporting characters making an appearance here. We do get an appearance by a younger Cat Grant (Eliza Helm) hunting down the story about what is really happening in Midvale (which is having quite a bit of good fortune thanks to Kara's super-heroics under the radar) further suggesting we may see the current Cat return to the show prior to the series' end. As for the younger Kara and Alex, the episode explores well-covered ground concerning Alex's overprotective nature towards Kara and her disapproval at Kara using her powers and putting her secret, and her family, at risk. It's fine to bring them back one last time, but did this really need to be a two-part episode?