NCIS: Sydney will do whatever it takes to crack the case of a rogue assassin on the run during NCIS Special Agent DeShawn Jackson's chaotic first day as boss.

When a young girl finds the body of a former U.S. Navy officer floating in the harbor, the team is led to an 18th-century sailing ship hosting a pirate-themed wedding, where DeShawn and Evie go undercover to investigate. Meanwhile, Mackey and JD are pulled in to prevent a potential tragedy on the harbor that could rip the U.S.-Australia alliance apart.