BBC America is debuting a new drama called Killing Eve, and trust us, it’s about to be your new obsession. If you have an Orphan Black-shaped hole in your TV life after that thriller bowed last year, Killing Eve will fill that void and then some.

The series stars Grey’s Anatomy alum Sandra Oh as Eve Polastri, a British intelligence agent whose obsession with a female assassin named Villanelle puts her at the head of a worldwide hunt for this cool-as-ice killer. Jodie Comer of The White Princess plays said assassin, and both ladies tell Brit + Co that these roles are a “total departure” from what fans are used to seeing them play.

When the series begins, Eve is just getting her feet wet in the world of high-stakes spy adventure, having previously been a mid-level intelligence officer. Villanelle, meanwhile, is quite comfortable in her assassin role, having killed people all over the world without asking questions. But Comer says that is all about to change for her character.

“She has a handler, Constantine, who essentially tells her what she needs to do and when she needs to do it and she is to ask no questions,” Comer tells us. “And that works until, as the story progresses, she starts querying things and asking more questions and that doesn’t go down too well.”

Part of Villanelle’s journey involves finding out about this female intelligence officer who is obsessed with hunting her down, and Villanelle begins an obsession of her own. Eve and Villanelle eventually meet — that’s not a spoiler, it’s in the trailer for the series — and their mutual fascination with each other makes the confrontation less adversarial than one might think.

“There is definitely respect between the two women,” says Comer. “There’s a huge curiosity as well, from both sides. It’s kind of weird, when Villanelle meets [Eve], she kind of just wants to spend time with her and Eve’s like, ‘What the f*ck?!’ There’s a huge respect and they’re both kind of seeking out something within each other. There’s something that Villanelle brings out in Eve and Eve brings out in Villanelle and they don’t know quite what it is and that’s why they’re so drawn to each other. With Villanelle it starts to become an obsession and I think it’s the same for Eve’s character.”

“They are barreling towards each other for reasons they don’t know,” adds Oh. “They need something from each other. And that’s what the show is about, discovering what they need from each other. Who’s going to kill? Who’s going to save? Who’s really hunting and who’s really killing? I think there’s a bunch of saving in there.”

Oh also says that while Villanelle may seem like the darker character, don’t be fooled by Eve’s more humorous, light-hearted nature — the two women are more alike than you think.

“There are certain elements you can see in Villanelle — the fact that she’s free, the fact that she traffics in this very dark world — [that] are things that are obviously missing in Eve’s life. For all intents and purposes, she has a fine life, but she happens to be a person who wants more.”

But that’s what Oh likes most about her character. Eve unapologetically wants more out of life, even if she can’t really admit that initially.

“I really don’t think Eve is very conscious of why she does what she does. She’s not a very conscious character, which I really like,” says Oh. “The character is discovering stuff all the time. ‘I don’t know why I’m attracted to this darkness. Do I have darkness?’ She would probably say, ‘No, I’m fine.'”

But Eve is decidedly not fine, and that is going to become more apparent as the series goes on. The same goes for Villanelle, though her darkness is readily apparent right from the start. But Comer tells us that there’s a whole complicated backstory with Villanelle that is going to come into play as the season progresses.

“One thing that I did before we started shooting, I sat down with [creator Phoebe Waller-Bridge] and we had a whole timeline from when Villanelle was born to when she lived in Russia, what happened in Russia, how she moved to France — which was definitely needed. I couldn’t fathom why she was killing people and how effortlessly and with no remorse, I couldn’t get my head around it. Just what events have shaped her life, does she have any family? All these things were definitely at the forefront of my mind,” says Comer, adding that her character’s darkness definitely makes her “capable of anything.”

Killing Eve premieres Sunday, April 8, at 8 pm ET/PT on BBC America. Watch the first episode now via Brit + Co.’s sneak preview.

(photos via BBC America)