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.

NCIS agents from Washington, D.C., Los Angeles, and Hawai'i are all in D.C. to attend the retirement party of a beloved Federal Law Enforcement Training Center (FLETC) professor, finding themselves jointly investigating his shocking suicide.