Other non returning cast members included Jeremy Lindsay Taylor (Buffer), whose position has been filled by Conrad Coleby (Dutchy) and Jay Ryan (Spider), replaced by Danielle Horvat (Bird).

[citation needed] The crew of HMAS Hammersley race to save the life of an American citizen when they receive her frantic mayday, but when they reach her boat they find no-one on board and a bomb hidden below decks.

Mike's heartfelt promise to rescue the woman is questioned by NavCom who ask think he has been at sea too long, and it is time he takes the promotion he is due and moves to a shore-posting.

Joined by their new buffer, Dylan "Dutchy" Mullholland (Conrad Coleby), the Hammersley crew resume their search for the missing woman, but when they find her she has been interrogated for information on the United States Ambassador, who is on a vacation at a classified location.

During a night of R & R, 2Dads gets into a bar brawl over the capture of crocodiles taken from Australian waters illegally, and then has to decide whether to reveal that the CO was involved or get discharged from the Navy.

While relaxing at a tropical island resort, a young girl is kidnapped, prompting the crew of HMAS Hammersley to cut their break short in pursuit of the suspects.

During repairs, the crew take a break on a nearby seemingly deserted island, where they encounter a small carbon neutral community, and Bomber strikes up a relationship with one of the residents.

Forced to stop at Tiparu Island for additional medical supplies, the crew comes across the escaped convicts who high-jacked the plane and a man claiming to be the pilot.

A comical scene ensues as the crew of the Hammersley are brushing up their first aid skills and Swain asks 2Dads to demonstrate CPR on Charge.

But the mood changes when they encounter an unknown object in the water, and on bringing on-board discover that it is a freezer full of human organs, most likely destined for the black market.

En route to Karumba to provide flood relief, Hammersley receives a mayday from a vessel that was rammed by a cattle barge.

Charge, who faked a cold to avoid going on the dive, has doubts about the theory – Shark Attacks are extremely rare in the area and the damage to the leg doesn't match with bite marks.

At the village, kids are playing with a live grenade, which explodes, injuring the chief’s son, Tiken (Joel Lok), and sparking tensions between the locals.

Swain and Dutchy remain behind to assist with treating the boy as Hammersley heads off to continue the aid drop to Kaiten Island.

Back on Vatinaie, the chief, Suil (Ariu Lang Sio), has been shot in a conflict with some of the younger villagers who are trying to gain control.

Swain, Dutchy and the doctor, Sarah, with help from Suil and some of his family, decide to set off with the injured boy towards the other side of the island, hoping to outrun the young men.

On watch, Swain hears the young men from the village passing close by and the tension of the situation leads to a romantic moment with Sarah.

Soon after, Hammersley responds to another mayday, but this time find nothing amiss after Fraser surreptitiously switches the coordinates, and in the process blames the XO for the mix-up.

Meanwhile, Swain and XO find discrepancies in the story of Eliza Lang (Alex Ashton), the diver's wife, and suspect she may have orchestrated the drowning to obtain her husband's life insurance.

While boarding a Foreign Fishing Vessel (FFV), Bomber is groped by a fisherman and responds with pepper spray, accidentally hitting RO.

The medical emergency and resulting chaos allows the fishing crew to retake control of their boat, putting the XO's life at greater risk.

While docked at Orlan Island, Mike leaps to the rescue of the baby son of a grateful Anton Gorski (Valentino Del Toro), who had fallen off the wharf in a carriage.

Hammersley receives a pan-pan call from Stuart Mason (Jason Hayes), captain of an oceanographic vessel, who had spotted a body being dumped from a fishing boat.

After retrieving the body, identified as a drug smuggler, the crew boards a nearby fishing vessel matching the description given by Mason, but find nothing.

After helping him back to his ship, Mike is mistaken for Mason by a drug smuggler, Cavenaugh, who is looking to hire the oceanographic vessel to search for a minisub.

Managing to track down the oceanographic vessel, Hammersley's crew board and find Gorski's wife, Sylvanna, (Alin Sumarwata) tied up.