Beckett is contacted by John Raglan, the investigating detective on the homicide of her mother, who is dying and, tormented by his conscience, has information about the original failed investigation. But before he can pass it on, Raglan is murdered by a sniper in front of Castle and Beckett; determined to uncover what Raglan knew, Beckett begins to investigate old leads in her mother's murder, but is soon suspended from the case after her integrity is challenged by her emotional investment. As Ryan and Esposito continue the investigation, Castle and Beckett launch their own unofficial inquiries -- and both teams soon find themselves up against a mysterious individual with power and influence who is willing to kill to ensure his secrets remain safe.
—Scotty