After a firefight and a concussion wreak havoc on Tony's mind, Tony needs Gibbs to help him regain his memories of the investigation.
When a beloved Marine is fatally stabbed just after returning from Afghanistan, the team makes a surprising discovery about his past.
NCIS discovers a connection between McGee's grandmother (Lily Tomlin) and the murder of a Navy lieutenant.
An investigation begins after a contract assassin targets a Navy lieutenant commander; information about Abby's family emerges after tests for a kidney donation.
The team searches an abandoned cargo vessel for a killer after a coast guard officer is gunned down; McGee and Tony search for Gibbs' perfect match.
Evidence reveals that a Navy lieutenant was killed by being force-fed too much liquid; Gibbs meets Ducky's new romantic interest (Cheryl Ladd).
The team looks for answers when the current husband of Diane, Gibbs' and Fornell's ex-wife, is abducted.
The team finds a problem with the DNA samples collected while investigating the crash of a military plane that was transporting caskets.
Ziva and Gibbs head to a missing Marine's last-known whereabouts in Afghanistan; Tony's fears are revealed.
Anthony DiNozzo Sr. (Robert Wagner) is found in a car with no memory of the previous night and a dead body in the trunk; Tony goes against orders as he tries to establish his father's innocence.
When a Navy captain is killed, the team must find and protect his pregnant companion; Jimmy brings his fiancee's father to work.
The investigation of a Navy commander's murder leads the team to E.J. Barrett, and a second death prompts the team to protect E.J. as they hunt the killer.
NCIS investigates the death of a Navy lieutenant whose body was found at a construction site; Ziva thinks about her future.
Gibbs questions the choices he has made during the course of his life when a man pulls a gun on him at a diner.
A dead Navy captain dressed in an unusual costume underneath his uniform leads the team to discover a secret society; DiNozzo is forced to work with his ex-fiancee (Perrey Reeves).
Gibbs clashes with Dr. Samantha Ryan (Jamie Lee Curtis) of the PsyOps Division when a Navy reservist is found dead from a suspected suicide; DiNozzo sees McGee's paycheck.
Security at a Naval research laboratory is in jeopardy after a petty officer's murder links to an arms dealer; probationer Ned Dorneget sucks up to Gibbs.
When classified information is leaked, the Secretary of the Navy (Matt Craven) investigates alongside Gibbs and Dr. Samantha Ryan (Jamie Lee Curtis).
The investigation into a petty officer's murder leads the team to its prime suspect: Director Vance's brother-in-law.
Tony helps Ziva and her mentor look for a missing Marine lieutenant in Colombia; Jimmy Palmer chooses his best man.
The team works with the Baltimore police to investigate a warehouse fire that revealed missing Navy documents that could potentially threaten national security; Tony reunites with a boy from his past.
An investigation into a fire on a Navy vessel leads to a discovery that elevates security at Navy facilities worldwide; Ziva and DiNozzo are called in when an explosive device is found on a ship in Italy.
As the team searches for a terrorist targeting the Navy, a bug is found in a probationary agent's tooth; Jimmy Palmer has a bachelor party.