Spoiler: A Look at the Premiere with a Guest Star

William Keck gave fans a look into the premiere with Lisa Edelstein in TV Guide's Keck's Exclusives.  To find out what they revealed look below.

Is this the woman who will come between Rick Castle (Nathan Fillion) and Kate Beckett (Stana Katic)? Former House star Lisa Edelstein begins a three-episode Castle arc as investigator Rachel McCord, who is connected to Beckett's job offer in Washington, D.C., in the ABC drama's Sept. 23 premiere. "McCord becomes a mentor to Beckett and doesn't quite understand why Castle is hanging around," Edelstein says. "What McCord's done with her life is really inspiring and tempting to Beckett, but it is also threatening to the way of life Beckett's chosen so far."

For the full article check out Keck's Exclusives.