Kai goes undercover with one of Hawai`i's oldest surf gangs when a petty officer who's trying to help wayward kids find a new path in the Marines is murdered.

When a Japanese sailor is killed on American soil and evidence links the case to the previous murder of the victim's girlfriend back in Japan, NCIS must find the murderer before the wrong person is accused and the case triggers a diplomatic crisis. Also, Captain Milius makes a personal request to Tennant.