Prime Video's latest action-packed spy thriller from Russo Brothers' AGBO, Citadel, is brimming with a strong cast, questionable characters, and riveting relationships. The high-stakes series follows spies from an independent global agency eight years after its fall in uncovering the moles within and the fight against Manticore, the operatives responsible for the destruction.

Citadel's cast features Richard Madden as Mason Kane and Kyle, a single character battling through the formal life he used to know and the one he's built quietly after the destruction. Stanley Tucci stars as Bernard Orlick, an operative of Citadel determined to ensure Manticore doesn't prevail. In an interview with CBR, Madden and Tucci broke down their character motives, working together, as well as the episode they're most eager for fans to see.

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CBR: Romance is a really interesting sub-genre in Citadel, but at the same time, trust is a heavy subject to tackle in high-stakes action. How would you describe the importance of romance for your character?

Richard Madden: I think that's what's quite deceiving about [Citadel], and something I worked out as the piece went on, filming-wise. You've got this spy who, in [many] ways, is very dark. As [Citadel] progresses, I think you find his real motivation -- his love, which is expressed [poorly], I think. [laughs] And then, on the flip side, I get to play Kyle, who's connected to all that romance and love on the forefront. It's right in front of him, and very tactile to him. That, [to] me, was interesting.

Stanley, on the topic of trust, your character says in the trailer, "Why should you trust me? I'm a spy." How did you approach such a morally gray character and layering him?

Stanley Tucci: I think that in the end, he is a trustworthy person, but there are times when he has to lie or, sort of, lies by omission in order to get what he wants. He wants to protect Kyle. He likes him, and he cares about his family -- he cares about all of them as this sort of avuncular figure in this piece. But the overall thing he cares most about is Citadel itself, and he knows that sacrifices have to be made. Whether it's somebody he loves, like these people or himself, in order to have Citadel survive and destroy Manticore -- that's the primary objective. That's the thing that causes him to lie, cheat, and deceive. It's ultimately for good.

Mason (Madden) and Bernard (Tucci) talking on opposite sides of a table in Citadel

Going off of that, what's the most rewarding part of working together and having your characters work together and the two of you as actors?

Madden: I'm [very] thankful I get to work with Stanley. We've never worked together before, and I think Stanley brings out the best in my character and me as an actor as well, especially with something that's so life or death stakes, so action-packed, and drama-driven. Stanley can bring some real joy out of me on set that feeds into this character, too, as the real connection. Even though [Kyle] has no memories, they instantly have a connection, and he knows it. I think that much is mirroring life because I got to make a new friend, too.

Tucci: I feel the same way. I've done many movies over the years, and you don't always hit it off with people. You don't always become their friend. In this case, we hit it off, and we became friends. It makes a big difference when you're working long hours, and you're doing stuff in creating this bizarre relationship on-screen -- that is sort of on this emotional quicksand. Nobody ever knows quite where anybody is. To have that bond in real life makes a big difference. It also just makes it more fun. Movie making is a very tedious craft, let's face it. You're there for long hours; you're repeating the same thing over and over again. To have somebody whose company you could enjoy, with whom you could laugh, and when you have a great crew and great directors, like the Russo Brothers, it really makes a big difference because it's a lot of work.

What's the episode you two are most looking forward to for fans to see? Without spoilers.

Madden: Episode 6.

Tucci: Yeah!

Citadel premieres exclusively on Prime Video with two episodes starting April 28, and a new episode every Friday.