The gang is sad about Kate's death, and they remember her and try to deal with her loss. Ari visits Abby's lab, and the NCIS has a new leader.
As Ducky meets Ari, Tony pursues Ziva. On the other hand, Ari betrays Israel and Mossad.
Gibbs interrogates a convicted serial murderer he captured ten years ago.
Ziva is back. The remains of a UA Marine staff sergeant are discovered in a 140-year-old iron casket at the Smithsonian Institution, prompting Gibbs and the team to investigate. The team searches for clues, follows a map, and deduces the story.
As a sailor dies from a gunshot wound, Gibbs and his team suspect the identity of the dead man, but they soon realize there is more to it.
The NCIS looks into the disappearance of two wives of deployed enlisted Marines.
A six-year-old child witnesses the kidnapping of his father, a Naval officer who works with a highly classified internet encryption system. The kid contacts NCIS, and Gibbs and the team start investigating, to finally solve the crimes and rescue the dad.
Going undercover, Tony and Ziva solve a mysterious murder mystery involving a married couple.
A young woman's amputated legs appear on a Marine Corps base, and the team tries to make sense of what's going on.
The squad works to clear McGee's name after he shoots an unarmed undercover officer.
Three models participate in a reality program at Marine Corps Base Quantico, and one of them soon dies.
Tony and Ziva are investigating at a port when they stumble into unexpected criminal activities and become imprisoned inside a cargo container.
A naval officer is kidnapped, so Gibbs and his team get involved in trying to solve the thorny case.
Two Korean spouses of Marine sergeants are killed in execution-style killings, and as the NCIS starts to investigate, a third wife goes missing.
Gibbs, Tony, and Ziva discover a decapitated skull in a cooler in the trunk of one of the automobiles while busting three Navy enlisted guys running an automotive chop shop. The gang discovers the remaining body and the backstory.
An ambulance catches fire and explodes while carrying the body of a marine corporal who died in a car wreck, so Gibbs and his team investigate.
When a bear eats part of the body of a murdered junior Navy officer in Shenandoah National Park, Gibbs takes over the investigation and hunts for the perpetrator.
The squad must prevent a pupil from detonating a bomb after holding six colleagues hostage.
A kid playing on a frozen pond notices a man's body beneath the surface. Gibbs and his team investigate and discover three additional corpses.
Tony and Ziva go to the home of a naval cryptologist and find her dead before she was supposed to be interrogated at NCIS. As investigations take place, suspicion of murder emerges.
After a couple enters a Navy Lodge hotel and discovers gory human body parts, the Gibbs team starts looking into the matter.
A suspect passes out and dies while being held by Ziva, so she becomes a suspect, not a detective, while the other members investigate.
An explosion strikes aboard a Turkish flagship, killing one person and leaving Gibbs unconscious and wounded, and the crew investigates.
Gibbs regains consciousness; however, his memory has been erased since 1991, and he tries to regain it.