After a malnourished and confused 9-year-old is found hiding in a storage unit, the team reopens an old missing persons case that Special Agent Ziva David had a personal interest in.
McGee reluctantly visits his former high school after the unique computer password he used as a teenager is linked to the murder of a department of defense contractor.
The team investigates the murder of a Marine Major believed to have been killed in the 9/11 attack on the Pentagon after human remains are discovered at a construction site.
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 that is offering him a highly paid position.
After the team finds a secret government bank account that's funding a nationwide network of vigilante justice, they must determine who is acting as judge and jury.
The team investigates the murder of Marine Gunnery Sergeant Richard Wilson who was hailed as a war hero for his efforts overseas; Gibbs turns to Dr. Confalone for advice after uncharacteristically abandoning the team at a crime scene.
Fornell pleads with Gibbs to do whatever is necessary to take down drug dealers in the area after his daughter is hospitalized from a drug overdose; Gibbs is haunted by aspects of the case.
Ziva surprises Gibbs with a cryptic warning, prompting him to question why she remained underground for years while being presumed dead, and what led to her return.
After a body is found hidden under an 18-wheeler delivering to the Navy yard, the team tracks the vehicle's previous locations to pinpoint the crime scene and suspect; Sloane encourages the team to talk about Ziva's recent reappearance.
The team links a bizarre crime scene at Arlington National Cemetery to a string of attacks on homeless veterans; Vance orders McGee, Bishop and Torres to complete hours of evidence garage cleanup duty for withholding information.
The team investigates a Marine Corporal after she finds a gun in her house. The gun is linked to a murder, but the Marine had no connection with the victim and was fast asleep when the crime was committed.
When a Petty Officer's son is found murdered at his welcome home from prison party, evidence suggests that Kasie's lifelong best friend, Dante Brown, is the suspect.
The NCIS team investigates the murder of a musician in the Navy's most elite band, which performs at diplomatic events around the world. Gibbs gives McGee the lead when he unexpectedly takes some leave time.
The team investigates a petty officer's murder that was live-streamed on a popular gaming app. Also, Gibbs is asked to look after his 9-year-old neighbor, Phineas, when his mom must leave on a last-minute trip.