Kevin Rahm and Tea Leoni Kevin Rahm and Tea Leoni

Secretary of State Elizabeth McCord (Téa Leoni) has scored some major victories, as well as a few defeats, in her first months in office on Madam Secretary. However, her biggest tests are yet to come.

"She's remained the same person with the same principles, but I think what we've done is test the strength of them," creator Barbara Hall tells TVGuide.com. "It's not going to be about her perfect wins, it's going to be about great challenges for her. And so we're going to get to see how she continues to manage those issues as they come up."

The freshman drama, which earned a Season 2 renewal last month, returns on Sunday (8/7c, CBS) with the first of a three-episode arc about the mysterious circumstances surrounding the death of her predecessor, Secretary Marsh, as well as the equally mysterious death of Elizabeth's former CIA friend George, who passed away just hours after warning her about Marsh's demise. It's a mystery that has weighed heavy on Elizabeth, and on fans, since the pilot episode, but Hall, along with executive producer Lori McCreary, promise there will be answers soon. The two spoke with TVGuide.com about all that, as well as the future of Dalton's administration, the intimidating new face in the State Department and Season 2:

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What can you say about the upcoming three-episode arc?
Barbara Hall:
This is the trilogy where we sort of take everybody into the heart of what the conspiracy was all about and it really the events unfold in real time with some political events that are already occurring. It's up to Elizabeth and everybody to connect the dots. So this is really where we get into the heart of it. There will be other elements of it that we play out through the rest of the season. But the next three are really where we take people into the heart of what's happening.

Obviously Elizabeth has a lot of close ties to this because of George's death and her history with the president. How will this affect her both professionally as well as personally as we dive into this?
Hall:
I think because it's related to her past working relationships in the CIA and it's also relates to her present working relationships in the State Department. But I think it really tests loyalties. It makes her question who's with her, who's against her and sort of gives that Washington feel, or real-world feel when the stakes are high.
Lori McCreary: I also think it ties into both her current situation as a diplomat and her CIA ties, and it's the perfect situation for this Secretary of State at this time in this world to come in and help solve. I think what people are going to see in the second half of the season is the vulnerability. In the pilot, there's this beautiful vulnerability in Elizabeth when she and Henry are questioning what to do. I think that that's going to come out as she's in the center of this world crisis.

What kind of implications will there be for the Dalton administration?
Hall:
Well I think definitely the investigation will have an impact on his administration and his re-election chances. And so we'll get into that and I think that's one of the things where it becomes such a major world event that that will be the question for the rest of the season: Is Dalton going to weather this? Is Elizabeth going to weather this? And what's that going to look like. I think it really affects every aspect of the White House.
McCreary: We have that interesting go-between with Russell Jackson who obviously wants a win for Dalton, but is going to be continued to be challenge by Elizabeth outside the box and problem-solving skills that he may or may not be happy with at any particular moment.

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You received an early renewal for Season 2. Since you knew so early you were coming back, is this investigation going to bleed into Season 2 or will it be resolved by the end of this season?
Hall:
We're going to try and resolve the biggest pieces of this conspiracy story, this mystery in this season. The fact is that everything that happens will definitely have tentacles that reach into second season, but we really want to get people to the end of this mystery by the season ender.
McCreary: I think there are emotional repercussions. Obviously her team is the former Secretary of State's team so that will continue into next season for sure.
Hall: Next season will be about how will this affect them? Like any other major event, it doesn't just end when we understand how it happened. It's the gift the keeps on giving. So this will go into next season in that regard.

Kevin Rahm (Mad Men) comes in as Mike B., a character who seems determined to help Elizabeth shake things up in the state department. What kind of strides will he make that? Hall: It's a character we wanted to bring in because we established that she inherited her staff and she had to get to know them and she has never questioned: Are these her people or not? He comes in as kind of a truth teller and somebody who can really give her a voice of Washington that's a little hard, and a little eye-opening. So he really does shake up her world and he makes her question her approach as she goes deeper into the heart of Washington and the situation volume is really turned up and she really has to stay on top of her game.
McCreary: He's the one guy who has nothing to lose of the people in the State Department, which I think lets him be a little harsher with the truth than her other staff members could be.

Should we be worried about her staff and who might come back and who might not?
Hall:
That is the idea is that we know the staff now, but now we have to question whether or not these are her people so I think it is a real concern and a real mystery as Mike B. comes in to examine that. McCreary: Especially as the broader investigation into what happened to Secretary Marsh comes into play.
Hall: It does question everybody's involvement eventually.

How will her marriage and her family be affected by what's going on at work?
Hall:
As we intensify her situation in Washington and as world events become intensified, that has a direct effect on her family. Everything is going to become a little heightened in the next series of episodes. McCreary: Especially one of the reasons that we wanted to have Henry's character be a religious scholar is that so many of today's big issues hutch on these religious and personal beliefs. Henry having a say and a deep insight into that is going to come into play as we go forward.

Madam Secretary returns Sunday at 8/7c on CBS. Who do you think is behind Secretary Marsh's death?

(Full disclosure: TVGuide.com is owned by CBS.)

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