Rhea Seehorn's audition for Better Call Saul began with a lie. Vince Gilligan and Peter Gould, Saul's co-creators, had ideas for personality traits they wanted Seehorn to embody — but her character's name and backstory were total fabrications, never to appear in the TV show itself.

That's the kind of secrecy an actor is forced to endure if they want to land a spot in a series as hotly anticipated as Better Call Saul — a prequel/spin-off from Breaking Bad, which is widely regarded as one of the best TV shows in history. Her audition was unusually thorough, and by the end, Seehorn felt like she had shown how she might be able to play a key role in the evolution of Saul Goodman.

But that didn't mean she was confident she had actually landed the role. "As an actor, there's a crippling self-deprecation: 'I couldn't possibly help them to tell that story,'" said Seehorn in an interview with The Week. "It isn't exactly something you assume you're going to get."

As it turns out, Seehorn needn't have worried — the show's creative team was instantly enamored of her intelligent, nuanced performance. "You can't take your eyes off her," Gould told me by phone, on a break from working on the show's upcoming third season. "She's fascinating."

When news first broke that AMC was developing a Saul Goodman-centric Breaking Bad spin-off, much of the conversation was centered around how the creators would incorporate fan-favorite characters from the parent series. Would Walter White and Jesse Pinkman return for cameos? How often would Mike Ehrmentraut appear? And could the slick-talking Saul — always a welcome presence, but hardly a commanding one — carry an entire series on his shoulders?

Those questions were understandable, but as it turns out, misguided. The real highlight of the series is Seehorn's Kim Wexler — a character who never appeared, or was even mentioned, over the course of Breaking Bad's five seasons. In Seehorn's hands, Kim is polished, hardworking, and self-aware, and she understands the well-intentioned but devious Jimmy McGill — later to remake himself as Saul Goodman — in a way that almost no one else does.

After a key supporting role throughout Better Call Saul's first season, Seehorn emerged as the secret star of Better Call Saul's second, which concluded last night. Kim's struggle to balance professional obligations, personal aspirations, and relationship entanglements provided the most interesting and complicated conflict of the second season, and Seehorn met the challenge in every scene.

The expanded role, Peter Gould explains, was a direct response to the strength of Seehorn's work in season one. "At the beginning of season two, we had a big question for ourselves: What is Jimmy really about?" says Gould. "We were stuck for a little while, and then we realized it was all about Kim. So much of what drives Jimmy is the fact that he's carrying a torch for Kim. And after seeing Rhea in season one, it was no wonder that he would."

The shoots could be technical and arduous. One of Kim's standout moments came in the fifth episode, when she spent hours calling anyone who might be in need of a law firm's assistance in an attempt to get back in the good graces of her boss. The sequence unfolds in a rapid-fire montage set to a Spanish-language cover of the classic Frank Sinatra classic "My Way":

The scene contains only brief snippets of dialogue — but to get more deeply into character, Seehorn wrote dialogue for the portions of the phone conversations on the other end of the line. "Cold-calling my friend's dentist that I heard might have a lawsuit brewing is a very different call than my college roommate's mom," she says.

Shooting that montage was time-consuming; Seehorn had to repeat the dozen phone conversations, with different inflections and moods, several times. Over the course of an entire day, Seehorn dashed between sets, switched in and out of costumes, and even adjusted minor details like the placement of her microphone pack to accommodate multiple camera angles.

But starring on a show like Better Call Saul doesn't mean you get access to all the secrets. Seehorn never got to read more than a single script at a time. She still doesn't know the long-term plan for Kim, and she doesn't think the show's creators know either. (One thing we do know for sure: Kim never appears in Breaking Bad, which gives the Better Call Saul writers the freedom to send Kim in any number of directions.)

That sense of spontaneity has Seehorn pleased with her role on the show, which AMC has already renewed for a third season. Unburdened from having to play the long game in her performance, she can focus on the tiny details that make up a complex human being. "You just play the small moments for what they are," Seehorn said. "If you end up having a huge montage scene or a huge monologue, it ends up feeling as lived-in as all your small moments."