Tragedy rocks HMAS Hammersley as the crew races to prevent a terrorist attack on a busy Australian port. Meanwhile, Kate and Dutchy discover ingredients for a radioactive 'dirty bomb' are being smuggled into Australia on illegal fishing boats, and Mike is stunned to realise SAS Officer Jim Roth has proposed to Kate - will he let the woman he loves marry another man?

The crew of the Hammersley are joined by a federal agent and go in search of an illegal fishing boat. Whilst on board the Navy find evidence on the boat and find the fishing boat crew start to exhibit symptoms of bird flu. One crew member faces a gruesome operation, while the federal agent learns that blackmail can work both ways.

Buffer becomes a marked man after providing evidence allowing the Hammersley team to arrest Ray Walsman, and among a team of UN observers later taken on board, is one man with murderous intent. Walsman meanwhile has escaped, but a quick thinking Mike has him back in custody.

The crew of Hammersley is rocked by the mysterious death of a much-loved shipmate. When valuable "Red Gold" coral is stolen from a dive boat, HMAS Hammersley is drawn into a web of murder, piracy and eco-terrorism. Then, Swain and Spider are kidnapped by an obsessed vigilante, determined to rid Australian waters of illegal fishing boats.

The Hammersley saves sailors from a sinking ship, only to learn they are diamond smugglers who will kill to save their cargo. Swain is kidnapped by smugglers and left trapped in their sinking ship. Will Buffer rescue him before the ship sinks? Mike is reprimanded by Navy brass over his obsession with the Bright Island mystery.

Bomber Brown and Spider Webb fall overboard and as the man of the watch, Buffer takes it hard that the two missing officers might drown. Meanwhile Buffer also deals with a personal tragedy.

Awaiting a call from his girlfriend, Buffer's attention is distracted by the Russian Special Forces tattoo on an aggressive passer by, which leads him to be inadvertently locked in a container on a suspect barge, heading upriver. Meanwhile, Commander Mike Flynn has recovered and is back in charge of the Hammersley, quickly reacting to a "mayday" call from the luxurious yacht owned by Ray Walsman.

Hammersley is tasked with protecting a shipment of nuclear waste from a terrorist attack. When a bomb is discovered on board, Robert and 2 Dads must set aside their differences to save Hammersley. Buffer falls victim to a practical joke and Robert is tricked into going on a drunken date, with disastrous results.

Dutchy and the crew are caught in a deadly fight for survival when a training exercise turns into a manhunt.

The crew uncovers a people smuggling racket, when they almost collide with a floating shipping container full of North Korean refugees. The Hammersley races to capture the smugglers’ ship and save the lives of their human cargo. Kate is wooed by a charming civilian sailor. Meanwhile, Mike is determined to solve the mystery of Ursula’s disappearance.

The Hammersley races to save a boatload of tourists from being murdered as part of a bizarre terrorist publicity stunt. Meanwhile, Swain and the crew help deliver the baby of a runaway teenager, found lost at sea with her criminal boyfriend. A series of emergencies at sea prevent Swain from attending the birth of his first baby.

After the Hammersley successfully pulls off the tricky evacuation of all the Australian citizens from an island in the Samaru Archipelago, it comes across an FFV which isn't what it pretends to be. Charge discovers first-hand exactly how dangerous his job can be. And Nikki and ET have to decide what to do now that they're working together.

When one of their mates is kidnapped by terrorists, the crew of Hammersley is in a desperate race to save his life.

Disaster looms for the Hammersley crew when a fire erupts in the engine room, after the mascot is stolen by a rival Patrol Boat crew. Meanwhile, an eye injury threatens to destroy Charge's career, and ET takes a vow of chastity in a desperate attempt to prove himself to Nikki.

After going on a blind date with an SAS commander, Kate believes her love life is starting to look up. When a French naval captain attempts to seduce Mike, he has to call on all his diplomacy skills. An illegal fishing boat is the subject of a perilous boarding.

Robert fails a drug test but is determined to prove his innocence. Meanwhile, the Hammersley uncovers a smuggling operation by Samaruian rebels which is designed to destabilise the government.

A change of command on HMAS Hammersley results in divided loyalties and the humiliation of the ship's most senior female officer. After a dangerous departure from Samaru, Commander Mike Flynn is recovering in hospital.

A thrilling rescue becomes a tragic mystery when a healthy young tourist dies suddenly on board Hammersley. Bomber and RO fight for their lives when an armed gang tries to seize control of Hammersley. Nicki receives a death threat while investigating ET's diving accident.

On patrol in the Arafura Sea, the Hammersley encounters an old adversary, an illegal foreign fishing vessel skippered by an infamous fisherman known as Hannibal. Robert is lost overboard in mysterious circumstances, sparking a major search and lives are at stake when Swain discovers rabies on board Hammersley.

Unresolved romantic tension has a dramatic effect on some of the Hammersley crew, after a savage mortar attack by insurgents on the Samaru island of Minatu. Mike and Jim are both critically injured during a bold rescue mission on Samaru. Meanwhile, Kate is made acting CO of the Hammersley. It’s up to Kate to handle a volatile beachside confrontation, and the medical evacuation of Mike.

In an explosive series climax, Mike and his crew takes extreme action to thwart an oil smuggling conspiracy and avenge ET's murder. Nikki risks everything to uncover the truth about ET's final moments. Kate is trapped in a deadly showdown with one of ET's killers.

There is something strange about the suspected foreign fishing vessel that a crew from Hammersley boards in the Timor Sea. On the deck are four Australian men who claim to be on a fishing trip, but Dutchy is suspicious of a fishing boat that seems to be carrying no bait, no nets, no fish and without any "blood and guts" on the deck. Further investigation reveals a cargo of illicit alcohol — and results in the XO being held hostage with a machete at her throat while the rest of her crew is sent packing.

When 2Dads goes missing on a scuba diving trip, Charge risks his life and career to find him. Mike creates a diplomatic incident when he searches a North Korean ship suspected of smuggling.

Kate uncovers a deadly conspiracy when she investigates a cluster of rare illnesses on a remote island. Hammersley is on the hunt for a ship suspected of dumping toxic chemicals into tropical waters.

The Hammersley uncovers a sophisticated drug smuggling network, with explosive results. Mike is convinced the Federal Police are covering up the poisoning death of a marine biologist. Kate is jealous of Mike's relationship with Ursula Morrell, while Nikki struggles to restrain her feelings for ET.