Atwell Opens Up About Love, Death & Whitney Frost in "Agent Carter's" Season Finale

SPOILER WARNING: The following interview discusses plot points and story developments from the "Agent Carter" Season 2 finale.

Throughout "Agent Carter's" second season, Peggy Carter has clashed with Whitney Frost over the latter's obsession with the otherworldly force known as Zero Matter. In tonight's season finale, with the fate of the world is on the line, Peggy must make some hard choices in order to stop her power-hungry nemesis. With the help of Jarvis, Sousa, Jack Thompson, Howard Stark and a few surprise allies, she just might stand a chance at succeeding -- even if not everyone makes it out alive.

However, there's more at stake than merely saving the world, as the ratings for "Agent Carter's" finale could determine whether the series returns for a third season.

Ahead of tonight's "Hollywood Ending," star Hayley Atwell spoke with CBR News about filming her climatic confrontation with Whitney Frost, Peggy and Sousa's romantic status, and a character's demise. Atwell also opened up about "Agent Carter's" potential third season, the possibility of appearing in other Marvel projects and her gratitude for the show's fans.

CBR News: It's all hands on deck to stop Whitney Frost and to rid the planet of Zero Matter. How much fun was it having the gang back together for one last hurrah?

Hayley Atwell: It was pretty difficult because we laugh too much, so it takes a long time to shoot everything. We're giggling and making each other laugh, especially James D'Arcy, Dominic Cooper and myself. We're kind of a bit like the Three Musketeers, which is very annoying for anyone else coming on to set, trying to do work. We get a bit silly. It's that kind of energy and atmosphere that I think brings out better work. We're all more relaxed, and we're giving the crew a good time. When it comes to "Action," we feel freer to just go for it.

Tonight's finale offers some closure on the Peggy/Sousa relationship. Why did it take so long for them to admit their feelings, and were you happy where they ultimately ended up?

It was like most things in terms of relationships in life. It was timing. Sousa and Peggy come into each other's lives at a time when she's grieving Captain America. She has no headspace, no heart space, to even entertain the idea of letting somebody else in. Of course, she's aware if she gets close to people, she puts their lives in danger. That's part of her life that's totally closed off in Season 1.

By Season 2, Peggy gets the call to go Los Angeles. Thompson very cruelly tells Peggy that Sousa asked for her, and she thinks that might be the beginning of a relationship. She gets there and realizes he's taken, and he didn't realize she was coming at all. That is a little bit painful and that makes Peggy shy again. It's kind of unfortunate that despite this great affection between them, circumstances -- and probably a shyness and a fear of rejection and of getting hurt -- actually blocks them being able to explore whether they'd even make a good couple. It's a very delicate situation for both of them that resolved itself with hope.

How did the challenge of dealing with Whitney Frost make Peggy a better agent?

Whitney is a nemesis in the sense that she is Peggy's equal, if not more intelligent than Peggy. Whitney has this extraordinary, inventive mind. There's a level of respect Peggy has for her, being in awe of what she's been able to do, despite the fact it's been used for evil.

In some ways, Whitney can be seen as the other side of the same coin as Peggy. That means the challenge is more thrilling for Peggy, and the stakes are higher. Most of the time she was working on this case, there was a genuine fear that she wouldn't be able to pull it off and Whitney Frost would win. But, that's the mark of a true hero. Despite the odds, she doesn't give up until it's over. Luckily, for her -- and the world -- she didn't.

Not everyone makes it out of this episode alive. How shocked were you by that development, and what it could mean for Season 3?

The thing with that is, yes, it was a bit of a shock. None of us really knew until the very end. What was kind of exciting about it is we don't know what the outcome of that is, and that is something we'd explore in Season 3. We don't really know, but it certainly raises the stakes for an exciting third season, whether or not that person comes back injured, or whether their death causes attention, or a need for revenge.

It's no secret that you've signed on to another ABC pilot. How will you feel if this is the last time we see Peggy Carter?

It's something I've tried not to entertain too much. There is a chance, from what I know, if both shows get picked up, I'll be doing both. Until I know one way or the other, I can't jump for joy or grieve.

The main thing I do have is the memories of two seasons of incredibly fulfilling and fun work, with a group of people that have come to be my friends and that I still speak to, especially James D'Arcy and Dominic Cooper. They are part of my personal life, and I find that very moving, that I could do a show like this and develop really good relationships with people. I'll always have that, if the network decides not to move forward with it. And if it does, it's great because I get to do it all over again, and even attempt to outdo myself with how much more fun I could possibly have in the third season. Either way, I'm looking at both outcomes as very positive ones, with a zen-like mentality of "What will be, will be."

Would you be up for appearing on "Agents of S.H.I.E.L.D." again?

It's not something I would rule out if it felt like it was relevant or important to their story, or if it put Peggy in an interesting light and gave me a challenge I hadn't done before. Likewise, if I got asked to do any part of Marvel film or TV. It's always a delight to go back and work with the Marvel family. They are a passionate bunch of people and really lovely.

Not many female characters from the Marvel Universe have headlined their own series. What has the character Peggy Carter and this experience meant to you?

That can be answered in a couple of ways. One of them is with the conventions I've been to, I get the chance to meet some of the fans. When you work for film and TV, you don't really know who you are performing for. In a lot of the plays I've done, you get a sense of who the audience is and what people respond to and what they like or dislike. You feel it in the audience. Going to these conventions was a great way of being able to engage with people who watch the show, who like Peggy, and you get to find out why.

I think everyone responded to the line in Season 1, "I know my value," and anything else, to Peggy, doesn't really matter. Lots of girls and boys have said, "It's such a great thing to say," and that they found it very empowering to hear someone on TV saying that. It was lovely. I love what I do. I feel very lucky to be in a position where I get to work every day on something that I love. The bonus is if one or two other people get something from it, then you feel like you've been helpful in some way.

There are so many aspects of who Peggy is, and so much more we can do with her and the show, if the ratings dictate there's enough of an audience. But, who knows? Because it's the Marvel Universe, I could come back. I could pop up again in 20 years.

"Agent Carter's" season finale, "Hollywood Ending," airs March 1 at 9 pm ET/PT on ABC