Callen and Sam work with Navy Capt. Harmon Rabb, Jr. to apprehend spies aboard the USS Allegiance. Hetty partners with Marine Lt. Col. Sarah "Mac" Mackenzie to neutralize a missile attack in the Middle East. Kensi and Deeks are trapped in a mobile CIA unit in Iraq while under attack by ISIS.
Faced with multiple cases worldwide, the NCIS team splits up, with Callen and Sam working with Mossad Agent Eliana Sapir in Tel Aviv, and Kensi partnering with DOJ Agent Lance Hamilton in Los Angeles.
Callen and Sam run protection detail for retired Navy Admiral Kilbride in an operation to locate a missing Naval intelligence officer.
While Callen and Sam are aboard the USS Allegiance, the ship is placed under quarantine for possible Ebola exposure. Also, Kensi and Deeks investigate the hug of a petty officer who recently departed the USS Allegiance and is linked to the Ebola exposure.
The NCIS team searches for a stolen painting valued at million after online chatter indicates the artwork is being sold on the black market to fund terrorist activity.
The NCIS team reluctantly aligns with two former criminals from England, Ricky Dorsey and Frankie Bolton, after a powerful arms dealer kidnaps Ricky's daughter in an attempt to obtain a dangerous weapons system.
The NCIS team links the theft of an undersea drone prototype to a video game streamer's elaborate party. Also, Callen and Sam cross paths again with insurance broker Katherine Casillas, who insures the gamer's property and processions.
After a Navy lieutenant disappears from the scene of a car accident, the NCIS team processes the crime scene and discovers his laptop is missing along with recently accessed confidential information for retired Navy SEALs.
Callen and Sam travel to San Francisco to search for Beale after he's kidnapped during a clandestine mission for Hetty.
Akhos Laos, a former black ops agent originally recruited and trained by Hetty Lange, returns to seek revenge on Hetty for the life she introduced him to.
While the team investigates the theft of a computer virus, Callen and Sam consider their future at the agency, Kensi and Deeks discuss having children, and Eric and Nell analyze the impact of Eric's undercover assignment on their relationship. Also, the team tracks Mara, a crooked upscale banker.
CIA Officer Veronica Stephens asks the NCIS team for help when an agricultural engineer Hetty asked her to bring to the United States disappears.
After a rise in deaths caused by black market opioid use, the NCIS team links the street drug to funding for terrorist activities.
The NCIS team investigates the hug of a Naval warfare engineer at a spoken poetry event. Also, Callen asks Nell to assist him in a worldwide search for Anna's whereabouts.
Anna Kolcheck returns to warn Callen that he is in danger and he must now work with an archenemy to stop an underground trafficking ring.