When an ATF agent goes missing, the agency seeks help from the NCIS team to investigate stolen military-grade weapons and locate the agent. Also, Callen and Anna continue to plan their wedding, Rountree’s sister interviews for medical school, and Sam encourages his father to take part in the drug trial.

The NCIS team continues the case with ATF and the stolen weapons. Also, Callen and Anna decide on an impromptu wedding.