'Castle': Jennifer Beals Teases 'Dramatic' Reunion and Beckett's New Dilemma

Karen Neal/ABC

"Castle's" Nathan Fillion, Stana Katic and Jennifer Beals

Jennifer Beals stops by the precinct for the first of two episodes on Castle -- and it turns out the former Chicago Code star has more history with novelist Richard Castle than previously thought.

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As Sophia Turner, Beals enters into the fray when a case involving an international conspiracy comes to U.S. soil, prompting her to work with the FBI to help close the books on it. "Sophia enlists Beckett and by extension Castle to help her with this case," Beals tells The Hollywood Reporter. "Thus, the reunion begins."

Turns out, Sophia was in a similar position Beckett currently finds herself in, which causes her past history with Castle to resurface again.

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"Sophia was the inspiration for Claire Strikes," Beals explains. "[She and Castle] have known each other in the past, 12 years I guess it was, so he wanted to have an up-and-close personal look at the life of a female CIA agent. He started following her in the way he's tracking Beckett."

When the two see each other again, it won't be another day at the office. Beals says their reunion is "pretty dramatic and it's not like, 'Oh, let's start this all over again.' She needs their help. There's a history there but it's not like, 'Let's get married.' "

But because Sophia and Beckett are, to a degree, one in the same, it begins to affect the working relationship already established between Castle and Beckett.

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"Beckett may see aspects of herself in Sophia or in that relationship. At a certain point, Sophia knows Castle well enough that they start to finish each other's sentences in the way that Beckett would finish Castle's sentences or Castle would finish her sentences," Beals observes, adding that as the two-parter plays out "the relationship with Castle becomes more and more clear."

For Beals, who didn't even have a script when she agreed to do Castle, it was important that she play a "mature and grounded" woman. "I didn't want to play two women going after the same man," she admits, teasing two scenes in the two-parter that she was particularly fond of (one between Sophia and Beckett "talking about their various relationships to Castle" and the second in the following episode "between Sophia and Castle that reveals quite a bit about their relationship and where it might be going").

By the end of the two-parter, Beckett may be rethinking her situation with Castle.

"You get more information about Castle and it makes Beckett think about a few things because if there's already been somebody who a character was based on, how special is she?," Beals teases.

Castle airs Mondays at 10 p.m. on ABC.