Stana Katic and Jack Coleman, <i>Castle</i> Stana Katic and Jack Coleman, Castle

On Castle's Season 5 premiere, Detective Kate Beckett opted against killing the man who was responsible for her mother's murder. But if given another chance, would she make the same choice again?

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That's the question hanging over Monday's episode (10/9c, ABC), which reintroduces the shadowy Senator William Bracken (guest star Jack Coleman). When Beckett (Stana Katic)and Castle (Nathan Fillion) find evidence that links their current murder victim to Bracken, Beckett seizes the opportunity to finally bring the man behind her mother's death to justice. But as complications arise, Beckett may once again be forced to think outside the law.

"This certainly extends the conversation that we started in the first episode for Beckett," creator Andrew W. Marlowe tells "What line is she willing to cross in her search for justice? Does she do things the right way? Or does she compromise her values in order to get the result that she wants?" Adds Coleman: "She's very much on the horns of a moral dilemma. Every fiber of her being is crying out for vengeance. But [if she kills him], what does she become? What does that say about her? There are no easy answers here."

In some ways, Beckett is perhaps wrestling against becoming Bracken, who Coleman describes as a Machiavellian operator who will do whatever it takes to protect his secrets — perhaps even bump off Beckett for good. "She has this thing hanging over his head," he says. "All he really wants to do with her is neutralize her and keep her from making his life miserable. But I'm sure if he felt like there were a way to really make this problem go away, he could very well go down that path."

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