Ritu Arya has a great time working with The Umbrella Academy costar David Castañeda, even when their characters are at odds.

In the fourth and final season of the hit Netflix series, a time jump reveals that Lila and Diego are married with two children, but their relationship isn’t entirely smooth sailing as they grapple with their lives without superpowers and their deteriorating relationship with one another.

Though fans of the onscreen couple will be sad to see their relationship woes, Arya tells PEOPLE that playing a bickering married couple with Castañeda were some of her favorite scenes of the season.

“It’s super easy working with David,” she explains. “We’ve been doing this for a while now, so [it was] a lot of fun actually getting to just let loose and play this new dynamic. It was really some of my favorite stuff when we got to just fight with each other and bicker. I loved filming that with him.”

Castañeda echoed those sentiments while speaking with PEOPLE at the season 4 premiere, noting that they have gotten into a familiar groove while filming together. “Wherever I run she runs, and wherever she runs I run, every time we work together,” he says. “Being able to work with her, it’s like putting on the old shoes, putting on the old sneakers. It’s amazing.”

David Castañeda and Ritu Arya at The Umbrella Academy premiere.MATT WINKELMEYER/GETTY

As Lila and Diego both try to find greater purpose in their lives this season, they’re thrown a major curveball as Lila accidentally gets stuck in a different timeline alongside Diego’s brother Five (Aidan Gallagher) and can’t find her way home.

With only each other for company, Lila and Five develop a romance as they are trapped on another timeline for seven years. Arya notes she was “quite shocked” when she read the twist in the script.

“A writer had accidentally told me that that was going to happen the year before, and I just assumed that it was a joke. I was like, ‘That would be really, really funny.’ Then when I read it, it was like, ‘Oh my gosh, they weren’t joking,’” she explains. Arya notes that filming those scenes was even more complicated as she and Gallagher shot completely out of order from their costars, doing some scenes from the series finale before even seeing the first episode.

“It was really, really fun getting to have this little bubble of a story separate from everything,” she adds. “It felt like that as well. It was like delirious. We were on night shoots, and we’re in the subway. I had a lot of fun with Aidan. It was then weird coming out of it. You sort of get immersed into the world.”

As for where Lila’s feelings lie between Diego and Five in that final episode, Arya notes that her character’s primary motivation has always been her children. “While she’s away, she misses her kids. It’s really all about her children,” she notes. “That’s what she was living for, just to come back, see her kids. When she does, I think it sort of throws a spanner in the works when she sees Diego. I don’t think she’s expecting to have feelings for him again. I think she’s really confused because she spent all this time with one person for years, so you’re naturally going to feel a certain way. Yeah, very torn, very torn.”

The Umbrella Academy season 4.COURTESY NETFLIX

As the series comes to a close, Arya says it’s been incredibly “emotional” saying goodbye to the series and her costars. “I’ve loved being on set with these people. It’s family,” she explains. “With a series like this, it’s been long-standing, and that really adds to your level of love and trust. It’s not something that I take for granted.”