Gibbs is assigned the role of acting director while the team searches worldwide for Director Vance's whereabouts.
A Navy lieutenant is found murdered in his hot tub; the team interviews families in the victim's peculiar neighborhood; Torres must face the consequences after a volatile night out with Palmer.
An agent is starstruck after the team investigates an explosion outside the home of a Navy SEAL and his wife, a popular reality TV star; Vance continues physical therapy for the injuries sustained when he was held hostage.
Gibbs' quiet vacation at his remote cabin is interrupted by a call from NCIS asking for his help to locate a robber hiding in the woods near him.
After a 50-year-old tape recording left by a murder victim is found, the team tries to exonerate the Marine serving a life sentence for the crime.
After NCIS arrives at a Halloween crime scene, Torres recognizes the victim as a friend from federal law enforcement training; Jimmy thinks his lab is haunted by ghosts after objects keep mysteriously moving.
A street artist's mural is stolen, and the investigation leads to a conspiracy regarding a Navy contractor and the safety of ocean mammals; Bishop shares a special connection with the street artist.
McGee and Bishop travel to Afghanistan after a murder case in the states is linked to a string of soldiers killed by friendly fire overseas; Kasie leaves the lab and accompanies Torres into the field to process additional forensic evidence.
The team begins an undercover stakeout when their lead suspect in an old unsolved case is released from prison.
The team's holiday plans are put on hold when a murder investigation leads to the discovery of a newborn baby who has no identification and no apparent ties to a family.
The secretary of defense shuts down Gibbs' murder investigation and demands that McGee and Torres be arrested for their actions in the case.
An old family friend pleads with Gibbs to join him on a road trip to search for a missing military ID bracelet; a Navy lieutenant in NCIS protective custody is poisoned by an infamous drug dealer.
A malnourished and confused 9-year-old girl is found hiding in a storage unit; the team suspects the girl is the daughter of a Navy recruit who disappeared 10 years ago; Bishop discovers notes that Special Agent Ziva David kept on the case.
McGee reluctantly visits his high school after the unique computer password he used as a teenager is linked to the murder of a department of defense contractor; an intruder breaks into McGee's home in an attempt to steal his high school computer.
The NCIS team investigates a man overboard fatality from a Navy destroyer at sea; Torres is frustrated with Vance's assignment to mentor three high school students.
Jimmy is torn between family and work after his father-in-law asks him to tamper with evidence in a current murder investigation; Ed's poker buddy offers to help with the case.
Director Vance is notified by the Pentagon that the nuclear submarine Gibbs and Bishop are aboard to conduct a murder investigation has gone radio silent.
Torres relies on his team's investigative skills after he wakes up on a dilapidated fishing boat and is covered in blood and unable to remember the last 12 hours.
Following an active shooter lockdown at a naval hospital, the team searches for a suspect who fled the scene; someone from Sloane's past is a key witness in the case.
After human remains are discovered at a construction site, NCIS investigates the murder of a Marine major believed to have been killed in the 9/11 attack on the Pentagon; a personal history with the victim drives Gibbs to solve the crime.
After entering cold case DNA into the system, Kasie solves a 30-year-old murder case, but a loophole in the legal system may set the suspect free; McGee visits an elite technology company in Silicon Valley that is offering him a high-paid position.
After NCIS finds a secret government bank account that's funding a nationwide network of vigilante justice, the team must determine who is acting as judge and jury.
The team investigates the murder of a Marine sergeant who was hailed as a war hero for his efforts overseas; Gibbs turns to Dr. Grace Confalone for advice after he uncharacteristically unravels and abandons his team at a crime scene investigation.
A former FBI agent pleads with Gibbs to do whatever is necessary to take down drug dealers after his daughter is hospitalized from an opiate overdose; Gibbs is haunted by the personal aspects of the case and his history with vigilante justice.