The death of an American seaman on a U.S. nuclear submarine during an AUKUS ceremony on Sydney Harbour is investigated in a joint effort between America's NCIS agents afloat and the Australian Federal Police.

When a shark spits out an arm wearing U.S. Navy equipment, the team's investigation tests the loyalty of a band of former Navy divers.

When JD's son is kidnapped by an international assassin in exchange for a wanted criminal in NCIS custody, the team frantically tries to get his son back safely without trading in a criminal.

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 petty officer is found murdered and frozen, it leads the team into a twisted underworld of seafood and sex trafficking.

With a Stinger missile and murderer in the wind, and Darwin's World War II Commemoration ceremony fast approaching, NCIS: Sydney races to prevent a deadly attack.