As the saying goes, desperate times call for desperate measures. So when Peggy is seriously injured during an altercation with Whitney Frost, she finds herself forced to turn to an unlikely ally to take on her heavy work: her Red Room-trained nemesis from Season 1, Dottie Underwood.

Bridget Regan returns to the world of "Agent Carter" in tonight's two-episode block, and according to the actor, she couldn't be more happy about kicking ass in the Marvel Cinematic Universe once again.

RELATED: Peggy Has a Terrible Idea in New "Agent Carter" Clip from "Life of the Party"

"Dottie is a strong, confident character, which is so fun to play," Regan told CBR News about her big return. " She's not just strong physically, but strong emotionally and mentally. We get to see that challenged. The writing in these episodes coming up is so delicious."

CBR News: Season 2 actually began with a kick-ass confrontation between Peggy and Dottie. How cool of a reintroduction was that?

Bridget Regan: I couldn't have imagined anything cooler. When I heard about the opening shot and how they were going to replicate the opening of Season 1, but it was going to be me, I nearly fell out of my chair. I was so excited. On the day when we shot it in that gorgeous bank, and we had that incredible crane shot that pulls out -- it couldn't have been cooler. There were the amazing costumes and then the fight scene. The season really started with a bang. We spent two days working on that fight, and it really shows. I loved all the choreography, that jump where I get to kick -- it was so fun to do all those kicks.

When we last saw Dottie, Peggy and Jack were questioning her. Where do we find Dottie when things pick up?

Sadly, right where they sent her -- in federal lockdown. She's looking quite bored, and then Peggy walks in. Immediately, Dottie can tell she's hurt from the way she's holding her body. It's bizarre. Peggy is in this disguise, and Dottie picks up straightaway that Peggy is there because she needs her help. Nothing could be more delightful to Dottie.

What makes Dottie right for this mission?

I think Peggy is left with no other option. There's no other woman who can handle this. She also can't tell anyone. You have to remember, this is the 1940s. Peggy is a singular woman working in the SSR right now. There's no other appropriate woman that could be Jarvis' date to this event besides Dottie. Peggy is left with no other choice.

Whether it's while Peggy interrogates Dottie or the two super-spies trade blows, what do you enjoy about the banter between them?

The thing that is great about Peggy and Dottie is, in a lot of ways, they're equals. Dottie has never experienced a woman like Peggy before. Unfortunately, twice now, Peggy has beaten Dottie. There's a competitive streak deep inside of Dottie that still wants to beat her, or still take her out. That original mission Dottie had is still in the back of her head -- but, there's also a friendship, now. Dottie believes they can really communicate and team-up together. I love that they put us together. Dottie is an unpredictable character, and you don't know what she's going to do.

During this mission, Dottie will of course Whitney Frost's special talents. What does Dottie make of Zero Matter? Is she horrified, or does she view it as a power up for grabs?

The thing with Dottie is, she's just like the audience, and every other character. She's completely surprised and astonished. She's never seen anything like it before. It's also out of her comfort zone. Dottie hasn't come up against something like this. She's going to tread with caution, but she knows this is an opportunity. We don't know what Dottie is going to do in terms of if she is going to team-up with Whitney. Is Whitney going to find her useful? We don't know. There's something about that Zero Matter that levels the playing field because Dottie has no special powers. She just has her training and her survival skills.

Season 1 gave audiences a small taste of what shaped Dottie. Will we learn more about her backstory, her moral code or what it means to be a Black Widow?

In the second hour, there are some really great scenes where we see what Dottie is made of in terms of her strength. But, then, she's challenged, which is such a gift. Dottie is a strong, confident character, which is so fun to play. She's not just strong physically, but strong emotionally and mentally. We get to see that challenged. The writing in these episodes coming up is so delicious. We see Dottie pushed into these more challenging moments.

There's an incredible line of dialogue coming up -- Vernon says to her, "You're a girl without a country; an assassin without a target." I love that. She's unpredictable now. In Season 1, Dottie was a soldier with her marching orders. She was working for Fennhoff, and there was comfort in that. She was doing what she was told. Now, Dottie doesn't have a boss. She's on her own. Is she just going to wreak more chaos and havoc? Or, is she going to team-up with someone? Where is this going? It's a really great place where the writers put her in because she doesn't know herself.

Starring Hayley Atwell and James D'Arcy, "Agent Carter" airs Tuesdays at 9 pm ET/PT on ABC.