When Gibbs and McGee travel to Russia to escort a computer engineer home, the mission is compromised and they must hide from a Russian mercenary group that is hunting them.
When a lieutenant is murdered on his way to meet the president, the team must determine if his death was a targeted hit or part of a recent series of muggings.
Ducky and Special Agent Bishop go to London to investigate when a case has a connection to one of Ducky's former friends.
The NCIS team pairs up with the FBI when a research scientist is murdered and the primary suspect is wanted by the Russian government.
A deceased man is spotted overboard during a Coast Guard and NCIS training exercise at sea; Gibbs winds up on a vessel commandeered by pirates.
The team examines multiple motives when a therapist married to a Navy commander is murdered; the team talks about Tony's dating habits, and Halloween costumes.
During a murder investigation, the team uncovers a fraudulent charity targeting those looking for missing military personnel; Tony considers adopting a stray cat that followed him home.
The team investigate a road accident that killed a Petty Officer while Gibbs tries to clear a Navy Hospital Corpsman accused of illegally providing medical aid to the victims of the crash.
Inclement weather keeps DiNozzo, Bishop and her husband at the Dulles airport, where they end up working a case involving an elevated terrorist threat.
When the city's internet is shut down three weeks before Christmas, the team consults with three imprisoned cyberterrorists.
The team investigates a series of crime scenes that appear to be copycats of previous cases; two of Gibbs' ex-wives show up at a crime scene.
A rescue mission in Syria reveals evidence that indicates an American was involved in a social worker's capture; DiNozzo's strange behavior is questioned.
An openly gay Navy lieutenant set to receive the Medal of Honor is murdered; Palmer gets ready for fatherhood.
A murdered Marine and alumnus of the military academy DiNozzo attended is found with a student's photograph in his hand; Bishop and her husband ask Gibbs and the team to dinner.
When an explosion rocks a summit on global terror, the team suspects Gibbs' archenemy is responsible; Gibbs tries to help Fornell after his wife's murder.
A murder victim turns out to have been living under an alias created for one of Gibbs' undercover cases from 20 years ago.
The team investigates the world of black market art when evidence in a murder case reveals that a rare painting has been swapped for a fake.
When a dead thief is found in a Marine's home, the NCIS team finds the calling card of a terror group the Department of Defense had been tracking.
A petty officer's murder results in a lead in a 40-year-old airport bombing case; McGee is upset that he was not briefed on the cold case.
When evidence calls for a joint investigation between NCIS and ATF, DiNozzo partners up with his girlfriend, Special Agent Zoé Keates; Anthony DiNozzo Sr. visits.
The team finds a link between a murder in Washington, D.C., and a terror group holding a Marine hostage overseas; DiNozzo is annoyed that McGee was chosen to be featured on recruitment brochures.
When a Navy ensign from the Office of Naval Intelligence is murdered, Special Agent Ned Dorneget (Matt Jones) from NCIS cyber operations helps investigate; Jake and Gibbs' friendship is revealed.
A case escalates into a global initiative when it's discovered that an international terrorist group that recruits children has been buying bombs off the black market.