Supergirl will feature a double dose of daddy issues during Monday’s episode.

After M’gann (Sharon Leal) calls J’onn (David Harewood) back to Mars, the Martian Manhunter will discover that he is, in fact, not the last Green Martian. Alias alum Carl Lumbly makes his debut as classic DC character M’yrnn J’onzz, a pacifist religious leader on Mars and J’onn’s father. But J’onn won’t be alone during his off-world trip, as Kara (Melissa Benoist) tags along.

“That episode feels like an Indiana Jones movie when I read it,” Benoist tells EW. “I immediately gave props to all the writers for that. It’s such an adventure. In Kara’s foray into embracing her alienness, it’s really great to see her, and it was great to feel her, being on another planet. She was used to space travel when she was a kid, so it does feel like it comes pretty natural to her, especially now that she gets to do it with J’onn and travel to J’onn’s home planet with this really important mission to save Mars. It’s a really fun and epic adventure. Those sets were amazing.”

However, M’yrnn will have choice words on how different his son has become, which speaks to the theme of what it means to be human this season. Fortunately, Kara can relate on all fronts. “She of all people has been there more than once thinking a family member is gone and then discovering that they are in fact alive with Non and Astra,” Benoist says. “I think that gives her leeway to react and be there for him in a way that she would’ve wanted people to be there for her when she went through the same.”

A little closer to home, Maggie (Floriana Lima) faces a tough reunion with her conservative and estranged dad Oscar (Carlos Bernard), whom she reconnects with when Eliza Danvers (Helen Slater) decides to throw brides-to-be Alex (Chyler Leigh) and Maggie a wedding shower. “It’s this interesting parallel where Alex doesn’t have her father there, so she’s encouraging Maggie saying, ‘Hey, have you thought about maybe reaching out?'” Leigh says. “You learn a lot more of the backstory behind what happened to Maggie. You understand where she’s really coming from and it’s heavy. Floriana just slayed it, like she just did so amazing in that episode. After all these years later, she’s facing a fear, in a sense, so she’s stepping to that and Alex is trying her best to — like with Kara — just be that supportive role for her.”

Check out this sneak peek from Monday’s episode: