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.

The discovery of an exsanguinated sailor takes NCIS: Sydney into the world of modern-day vampires, family feuds, bespoke vodka and a nocturnal matriarch with a penchant for blood.

When a Navy compliance officer is found dead in a waterhole from a snakebite, the team works to uncover the origin of the rare deadly taipan that is uncommon to the area where the officer was discovered.

When a U.S. petty officer's body is found in Sydney's historic and haunted Rocks area, a decades-old Navy Cross medal holds the clue to solving the murder, leading the team on a wild ghost chase to catch a killer.

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.

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.

The team races to save one of their own when Doc Roy and his dog are involved in a hostage situation at their local dog cafe.

When the suspicious death of an old Drug Squad colleague pulls Evie back into a secret undercover operation, DeShawn is torn between loyalty to his friend and loyalty to his team.

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.

The team is thrown into the murky world of online conspiracies after a car owned by a U.S. Navy cyber engineer explodes just as her teenage daughter was about to take a driving lesson.

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

The suspicious death of a US Navy chorister draws NCIS: Sydney into the world of obsessive fans, pop stars, and earworms, as they learn how deadly the music business can be.

When the body of a long-missing U.S. Naval engineer is discovered buried in concrete, the team enlists Doc Roy's old friend to assist in the investigation.

The suspected suicide of a former U.S. Navy SEAL leads NCIS: Sydney to a wellness retreat to investigate a group of his fellow former SEAL buddies.

The team battles searing temperatures to investigate the death of a U.S. Marine corporal killed during a joint training exercise between U.S. and Australian troops.

A glitzy tech launch turns into a disaster, leaving half of NCIS: Sydney trapped underground, and the others scrambling to save the day before the clock and the oxygen runs out.

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.

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.