A wealthy bachelor and ex-Marine, killed by a fall from a rooftop, turns out to have been living a double life. The OPS team search for a motive when it is discovered that he was murdered.
A notorious serial killer, who Brennan helped put behind bars, plays a deadly game with the forensic scientist.
Dee receives numerous e-mails on her social networking page from a stranger claiming to be her and Dennis' father.
Vance returns to partner up with Gibbs for a murder investigation connected to a former NCIS agent put away for evidence theft.
After Mac's father is released from prison, Mac and Charlie stage their own deaths to save their lives; Frank, Dee and Dennis find unique ways of dealing with the loss.