Agent Knight's past resurfaces when her ex-boyfriend, a National Parks Service agent, teams up with NCIS to investigate a campsite murder.

Parker discovers he's a victim of identity theft while investigating the unusual murder of a Navy ensign; Knight and Jimmy face hurdles in their relationship as their connection heightens.

NCIS works to solve the murder of a Marine private who appears to have been killed for helping an Afghan refugee. Also, Jimmy navigates the pressure of parenting his teenage daughter, who is eager to go out on an unchaperoned group date.

With the help of Knight's dad, NCIS works to unravel the mystery of a recently used service weapon belonging to a missing agent. Also, McGee is in a tailspin when DNA results reveal a close relative he was unaware of.

After discovering the remains of a Marine captain, the NCIS team travels to Texas to interrogate the suspected killer.