After an NSA analyst is found eaten by a shark, the team's investigation leads them to a cartel's money-laundering scheme and sends Callen into a mental asylum to find a key witness; Kensi struggles with her therapy.

After Sam's wife, Michelle, is taken from her home, the kidnappers demand the prison release of Tahir Khaled, Sam's arch nemesis, in exchange for information on her whereabouts.

During the murder investigation of a Navy Lieutenant on leave in Los Angeles, the NCIS team uncovers classified surveillance briefs she smuggled into the city that may have been sold to a foreign buyer.

The NCIS team partners with the State Department after the murder of an arms dealer is connected to a series of crimes seemingly executed by someone with elite special forces training. Also, Callen visits ATF Agent Anna Kolcheck in prison as she awaits her sentencing.

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.

When Sam's friend Tom Olsen finds himself being hunted down by enemies from his past, the NCIS team must find out who is after him.