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Get ready for a heavy dose of Danvers during Monday’s episode of Supergirl.

In the wake of the Sanvers breakup, Alex (Chyler Leigh) and Kara (Melissa Benoist) head home to Midvale for an episode that delves deeper into the Danvers sisters’ relationship. Through flashbacks that feature a young Kara (Isabel Vidovic) and a young Alex (Olivia Nikkanen), viewers will see how the traumatic experience of losing a childhood friend actually brought the sisters together.

“What’s really fun is you’ll get to see, through the way they interact, more about 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 tells EW.

Leigh likens the flashbacks to a Scooby-Doo-type murder mystery that will provide a lot of answers about how the two sisters were able to cement their relationship. “It’s this mystery that has to be solved, basically, and they have to work together, and so you really do get a better sense of seeing what that looked like and how they had to figure things out and quickly,” Leigh says. “We only got bits and pieces of that that we’ve seen in flashbacks in the past seasons, so this is one [episode] that’s really cool. I think the tone is going to be really different.”

On the flip side, Leigh says the present-day story line is more Thelma and Louise. “I’ll just say we snag a really sweet ride,” she says. “It was a lot of fun. We got to drive around in this really sweet car and just cruise, which was great. We were out in the open fields on a Vancouver day and we just got to hang out and have fun. I can’t wait to see it.”

Image zoom Robert Falconer/The CW

The point of the trip home is so that Alex can take her mind off her recent breakup with Maggie (Floriana Lima), but the sisters end up relying on each other as both are really suffering heartbreak — Mon-El (Chris Wood) was forced to leave Earth in the season 2 finale, effectively ending his relationship with Kara. “Kara and Alex can both lean on each other,” Leigh says. Benoist concurs: “Alex and Kara always manage to find each other when they most need each other. Their sisterhood is so powerful.”

The story line is part and parcel of the show trying to return to the sister dynamic that drove much of the first season, but was less prevalent in season 2. “I can’t tell you how happy I am about that,” Leigh says. “I’m so grateful for all of the Sanvers stuff, I will never not be supportive of that and just so grateful of that journey. But there’s a part of it that was really like, ‘I miss working with Melissa!’ In season 2, it’s almost like people sort of got sectioned off — it was like Kara and Mon-El, Hank and M’gann, and then it’s me and Maggie, and then it’s Winn and James.”

“Maybe the two of them got so involved in their romances last season,” Benoist adds, “which was wonderful and we need to discover that as people ourselves, but this season you’ll see them both support each other in loss. It’s only fitting that Kara runs into the fray for Alex because that’s what they do for each other. She just went through the same and Alex was there for her. Honestly, those have been my favorite scenes to shoot thus far this season just because Chyler and I have a really special relationship and we care about each other a lot. That kind of bleeds into the scenes.”

Leigh agrees, taking every chance she gets to rave about her on-screen sibling. “I just absolutely adore their relationship,” Leigh says. “I say it all the time, and people are probably like, ‘Yeah, right,’ but I love Melissa so much. So the both of us are really excited to hear that it was going to be a bigger focus this season. I feel like it brings more of that grounding and that heartbeat of the show back a bit.”

[Editor’s note: These interviews were completed prior to news of sexual harassment allegations against Supergirl executive producer Andrew Kreisberg.]

Supergirl airs Mondays at 8 p.m. ET on The CW.