A member of the team disappears while under cover; the team works alongside LAPD on a human-trafficking case that involves money laundering and drugs.
After a mysterious hit squad takes out a special agent on assignment, the NCIS team jumps into action before the next target is set.
Kensi and Deeks search for three Marines who go missing after an ambush; Nate returns from his mysterious assignment.
The team investigates the murder of a Marine who had top-level security clearance, and the corpse is missing a hand.
The team races against time to save a naval commander's daughter after seeing a video of her being buried alive.
Callen's former partner (Marisol Nichols) takes hostages at a Navy recruitment center.
After terrorists kill a state department employee and a plastic surgeon, the team searches for the only witness who can identify the killers' surgically altered faces.
Terrorist leaders are suspected of murdering a retired Army sergeant; Deek connects with a person of interest in the case.
The team searches for a missing book containing top-secret information, which belonged to an antiques dealer who was murdered.
Hetty and the team continue searching for an elusive book that has the attention of foreign security agencies.
While investigating a deadly dispute, Kensi connects with a discharged Navy intelligence officer who has post-traumatic stress disorder.
A body containing a top-secret residue is stolen from the autopsy room, leading the team to discover an experimental Navy tracking system; Callen challenges Hetty on the rock wall.
The team looks for the person responsible when classified pentagon documents are uploaded to a blog site.
Sam goes under cover as a prisoner to track down a terrorist group responsible for several bombings around the world.
Callen catches a man breaking into his house; the team discovers a shipment of counterfeit computer chips.
Suspicious of an undercover venture involving a deal between corrupt cops and military personnel, Callen and Sam try to expose the illegal operation by posing as California highway patrol officers.
When Deeks is shot during a convenience-store robbery, the team must determine if he was the assailants' intended target.
Sam resumes an alias and flies to Yemen to find the leader of a terrorist group and rescue a Saudi prince's son.
A Navy Intelligence commander is tracking the moves of a Venezuelan politician, then the officer disappears, leaving the team to wonder if the politician is now in danger.
When an attempted robbery takes place at a secure facility on a Marine base, Kensi must determine what the thief intended to steal.
After a rocket engine expert is killed, Eric goes under cover to ensure the classified technology used to build satellites is safe.
In order to protect his best friend and main informant, Deeks resumes a former alias that he dislikes.
A man pretending to be a Navy SEAL is set on fire, leading NCIS to information about the location of a stolen item from a past case that could be used to make a bomb.
Following Hetty's sudden resignation, Callen and the team try to unravel the mystery behind her disappearance.