All the Arrowverse shows – bar Legends of Tomorrow – have had their seasons cut short by the coronavirus, with Supergirl no different. Much like The Flash, season 5 of the Girl of Steel’s series will wrap up with its nineteenth episode. Thankfully, though not originally designed to fill that all-important slot, the installment – titled “Immortal Kombat” – will serve as a suitable finale as it brings back a surprising doppelgänger/guest star.
Brainy actor Jesse Rath confirmed to ComicBook.com this week that his real-life sister, Meaghan Rath, will be back to play the female Brainiac-5 from another universe. Rath debuted on the show earlier this season, in episode 5×10 “The Bottle Episode,” as an alternate version of Querl Dox who’d survived the Crisis by falling through a wormhole to Earth-Prime. She ended up joining the Big Brain, the hive mind of Coluans, but now we know she’ll be back in “Immortal Kombat.”
“I’m happy with that because I think [episode 619] is such a strong episode,” Rath said. “It’s a lot of cool Brainy stuff. You see Brainy’s plan come to fruition in that episode. And my sister, Meaghan Rath, returns to the show in  so I’m happy that  will be the finale. I think it’s a strong episode and it’ll do it justice.”
It’s not just the return of Lady Brainy that’ll make this episode special, either. As the synopsis below teases, the threat of Leviathan will come to a head, which will force Kara to put aside her differences with Lena Luthor in order to save the day. Obviously, things won’t be concluded as neatly as they should’ve been, but it sounds like a lot of the season’s important plot-threads will be drawn together in the finale nonetheless.
“Supergirl realizes that in order to stop Lex and Leviathan she must work with the one person she never thought she’d trust again – Lena. Nia keeps dreaming about Brainy but struggles with what the dreams are trying to tell her. Meanwhile, Brainy realizes there is only one way to stop Lex.”
Supergirl continues Sunday, May 10th with 5×18 “The Missing Link” before reaching its climax the following weekend on The CW.