After an unknown shooter causes chaos at an annual Thanksgiving 5K, time is of the essence for the NCIS team to find the culprit. Also, Kasie joins Knight for Thanksgiving lunch at Knight’s sister’s house.

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.

When a suspicious murder occurs in the classified section of the National Archive, NCIS must investigate a string of Russian spy encounters that may be linked to the crime. Also, Jimmy accidentally makes a confession that could change the course of his relationship with Knight.

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.