Abby becomes fixated on solving a murder; DiNozzo's latest fling leads to an interesting Halloween.

The NCIS team springs into action to find the assailant responsible for beating a Marine to death in his own backyard.

To Gibbs' displeasure, Special Agent E.J. Barrett returns to lead the investigation of a seaman's death that may be connected to a series of port-related murders. Meanwhile, Ziva finally introduces her boyfriend, Ray, to the team.

The line between McGee's personal and professional life is blurred when NCIS uncovers a connection between his grandmother and the murder of a Navy Lieutenant.

When a Navy lieutenant commander is found dead in a building under construction, NCIS must search for a killer while dealing with interruptions from her distraught detective husband. Meanwhile, Ray’s return has Ziva thinking about her future.

When a Navy Lieutenant who recently returned home from the Middle East is found dead from a brutal attack, the NCIS team questions the victim’s friend, Marine Captain Joe Wescott. Gibbs realizes the Captain is suffering from post-traumatic stress disorder, but knows his experience overseas may also provide a key link to the crime.

On leave from NCIS while still grieving the loss of his wife and his kids’ mother, Director Vance discovers unexpected personal information that causes him to question everything.

While the team takes a missing persons case, Tony is disturbed by Ziva's way of coping with her father's death.