Melissa Benoist as Kara, Chyler Leigh as Alex
In Season 3, episode 6 of “Supergirl,” Kara (Melissa Benoist) recalls a traumatic experience that brought her closer to her sister Alex (Chyler Leigh). The CW

Kara and Alex head home to Midvale in next week’s episode of “Supergirl.”

In an effort to take Alex’s (Chyler Leigh) mind off her recent split with Maggie (Floriana Lima), Kara (Melissa Benoist) takes her adoptive sister to their hometown of Midvale in Season 3, episode 6 of the CW series. But while there, as revealed in the synopsis for the hour, Kara recalls a painful memory of a childhood friend’s death and how that traumatic experience brought the Danvers sisters closer together.

“It’s a really, really cool flashback episode where you see kind of the initial dynamic between Kara and Alex and how that was really difficult for them in the beginning and sort of what the catalyst was for the turn in their relationship,” Leigh said of what fans can expect from the episode in a recent interview with Collider.

“You’ll get to see, through the way they interact, how their relationship started when Kara first came to Earth, how it grew, how it became so close and why they’re so close nowadays,” Benoist told Entertainment Weekly last September.

Executive producer Andrew Kreisberg also told Entertainment Weekly that the episode, aptly titled as “Midvale,” will feature the first adventure Kara and Alex went on when they were kids. “It’s this amazing episode, and we have these two amazing young actresses playing Kara and Alex,” the EP said. “It’s the episode that helps Alex get off of the couch [following her split from Maggie], so to speak.”

In the flashback scenes in the episode, young Kara is played by Izabela Vidovic. The high school-aged Alex, meanwhile, is portrayed by Olivia Nikkanen.

In previous seasons, young Kara was played by Malina Weissman, who is now a series regular on Netflix’s “A Series of Unfortunate Events.” Young Alex, meanwhile, was formerly played by Jordan Mazarati.

As seen in the trailer for the next episode, Erica Durance also makes an appearance as Kara’s biological mom Alura.

“Supergirl” Season 3, episode 6 airs on Monday, Nov. 13 at 8 p.m. EDT on The CW. Watch the trailer for the episode below: