Francie Swift, Dylan McDermott

Freshman CBS drama Hostages has added a potentially crucial piece to the highly serialized show's puzzle.

Francie Swift (Law & Order: SVU, Gossip Girl) has landed the possibly recurring role of Nina, the wife of Dylan McDermott's FBI agent-turned-terrorist Duncan Carlisle, TVGuide.com has learned exclusively. Although details about her character are scarce, sources say she will be central to the long-arc plot of the first season.

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Hostages
tells the story of Ellen Sanders (Toni Collette), a successful surgeon who's set to operate on the president of the United States. On the night before the surgery, however, Ellen and her family are taken hostage by Duncan and his team, who threaten to kill Ellen's family if she doesn't kill the president.

Although Duncan's wife appears in the hospital in a non-speaking role in the series' pilot, Nina will play into the story as the season progresses. Perhaps her character's health issues will illuminate exactly why Duncan would go against his badge and attempt to assassinate the POTUS?

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Besides her recurring roles on SVU and Gossip Girl, Swift has also appeared on The Good Wife, Elementary and Person of Interest. She also recently had a recurring role on the first season of Netflix's House of Cards.

Hostages premieres Monday, Sept. 23 at 10/9c on CBS. Swift is scheduled to first appear in the fourth episode.

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