Watch Castle (2009): The Final Nail Season 03 Episode 15 Online

Castle (2009): The Final Nail Season 03 Episode 15, Summary: Castle and Beckett find themselves on opposite sides of the case when Castle's old school friend emerges as the prime suspect in his own wife's murder. As they work to solve the crime, Castle comes to realize that one of two terrible things must be true... Either Detective Beckett is about to arrest an innocent man for murder, or his old friend is a cold-blooded killer.

This series will be aired on Monday on 14 February 2011 at 10:00 PM on NBC.