Paul Watson is allegedly shot by the Japanese whaling crew during a confrontation between the whaling factory ship Nisshin Maru and the Sea Shepherd vessel MV Steve Irwin. The episode then flashes back to the maiden launching and departure of the vessel from homeport three months earlier.

After weeks of searching, the Sea Shepherds finally spot a Japanese whaling ship, the harpoon vessel Yushin Maru #2. Captain Paul Watson devises a dangerous plan for two of his crew members to board the vessel and deliver a letter telling them to stop the killing of whales. He hopes to create an international incident, but his plan sparks a safety debate that divides the crew. Two volunteers enlist for the mission — Ben Potts and Giles Lane — and the crew braces for the worst as the men jump over the railing of the enemy ship. They are immediately tied up by the Japanese fishermen, and the Yushin speeds away with the two Shepherds still aboard.

Without negotiation and confrontation with the MV Steve Irwin, the Yushin Maru № 2 agreed to transfer Pottsy and Giles to a government ship that would then meet with the Steve Irwin at a rendezvous point to return the two members. 1st Mate Peter Brown decides to launch an attack on the Yushin Maru № 2 at dusk. Four crewmembers are sent on the Zodiac inflatable boat Delta to carry out the risky mission. After losing radio contact with them, recon pilot Chris Aultman, who was sent too late to survey the situation, reports that they are heading in the wrong direction and must return as night falls. The lone Delta was feared to be forever lost out in the middle of the dark, frigid, vast Antarctic Ocean. Fortunately, contact was finally made with the Delta, which eventually returns to the MV Steve Irwin over two hours later and behind schedule to retrieve Pottsy and Giles.

Giles Lane and Ben Potts safely return to the MV Steve Irwin. The crew then discovers that an unknown ship, allegedly spying for the Japanese whaling fleet, has been following them, decides to recon it from behind a tabletop iceberg for any military personnel aboard, and temporarily drives it away after seeing no sign of illegal military activity. The crew later plans to ambush the mystery ship, soon identified as the Fukuyoshi № 68, to prevent information about the Steve Irwin's whereabouts from being given to the rest of the whaling fleet. They plan to do this by boarding the vessel and sabotaging its communication equipment, shutting off any communication with anyone. Before the mission, a hydraulic crane used to launch the motor rafts somehow got damaged, jeopardizing the Sea Shepherd's mission.

The MV Steve Irwin experiences several technical difficulties, including a damaged engine, hydraulic crane, and helicopter. Running on only one engine, the ship must return to port at Melbourne, Australia to make repairs while the whaling continues. Some crewmembers decide to party and leave the operation. Upon arrival, they were welcomely greeted and cheered by the citizens, and by the police. Pottsy and Giles become instant celebrities on homecoming. After recruiting new members, the crew travels without its recon chopper and returns to the Southern Ocean only to find that the suspicious ship is still following them.

After noticing that the suspicious ship Fukuyoshi Maru № 68 has found and followed the MV Steve Irwin again, Watson unsuccessfully attempts to send four female crewmembers to board the vessel to deliver a warrant. This leads to a man's injured thumb and a woman's injured pelvis (Incidents not related). The Steve Irwin detects the Nisshin Maru on radar. At dusk, the entire ship experiences a power outage, leaving it drifting through an iceberg field without operating engines.

After power was restored to part of the ship, the MV Steve Irwin finally finds, follows, and comes face to face two times with the Japanese whaling factory ship Nisshin Maru, which Watson considers the "most evil" vessel in international waters. A pod of whales swims between the two "warring" ships, which eventually engage in a ship-to-ship "battle." The captain of the Nisshin Maru warned on a recorded message sent multiple times through a horn that "If you dare board this vessel, you will be taken into custody." Recruited Sea Shepherds are the first to strike, throwing stink bombs with Butyric acid onto the decks of the Nisshin Maru, which dwarfed the Steve Irwin in size, while its crew watches and films the Steve Irwin. The Japanese whalers claim that three of their crewmembers were injured by the stink bombs. When the two ships meet the second time, the Steve Irwin crew strikes first again while the Nisshin Maru crew, in return, threatens to use tear gas grenades and throws flash bombs. Watson fishes a metallic fragment from his vest and claims to have been shot. As Watson concluded that the second leg of the mission was successful, the Sea Shepherds claimed that they have saved about 500 whales. The Steve Irwin returns to Melbourne again before running out of fuel.

The former captain of the Ady Gil goes for a boarding attempt and one of the Sea Shepherd vessels goes dead in the water.

The Sea Shepherds embark on another dangerous campaign as whaling season begins in the Antarctic; a donation from former game-show host Bob Barker allows the group to purchase a former Norwegian whaling vessel.

A Japanese reconnaissance ship pursues the Steve Irwin; two members of the Andy Gil crew suffer illness and injury; the Bob Barker's engine fails two days into its journey.

The Sea Shepherds have been relentlessly followed by the whaling reconnaissance vessel for two weeks. They find themselves in a full-on engagement on the high seas as Captain Paul Watson orders a massive butyric acid bottle attack on his nemesis.

The Sea Shepherd's stealth boat, the Ady Gil, launches a sneak attack on the Japanese whaling reconnaissance vessel in an effort to break free of the tail and find the rest of the whaling fleet.

After nearly a month of searching, the Sea Shepherds have finally found their ultimate target: the world's only whale factory ship, the Nisshin Maru.

At the bottom of the world, a collision has just devastated one of the Sea Shepherds' vessels. The crew on the other vessel stand helpless on their deck, watching in horror as the Japanese vessel barrels through the Sea Shepherds' prized speedboat.

In the aftermath of the devastating loss of their stealth vessel, the Sea Shepherds have returned to the campaign with renewed passion and intensity. Now the two remaining ships are back on the hunt for the Japanese fleet.

With low oil and drinking water, and a damaged helicopter, the Sea Shepherds' hunt for the Japanese whaling fleet has been brought to a halt. While on their way back to port, the radar shows two colossal storms that they can't avoid.

As the Sea Shepherds approach the Nisshin Maru, they are suddenly surrounded by four whaling vessels. Suddenly, one of the Japanese vessels moves in dangerously close, and as the deck crew quickly braces themselves, the ships violently collide.

The Sea Shepherds refuse to be bullied by the Japanese fleet even though they're out numbered. The deckhands repel over the side of the ship to assess the damage from the collision and realize that there is a gash in the steel hull and water is pouring in.

The whalers face new attacks from the Sea Shepherds as they mount an attack with both the Bob Barker and Steve Irwin.

The former captain of the Ady Gil goes for a boarding attempt and one of the Sea Shepherd vessels goes dead in the water.

The whalers attempt to lose their attackers in an ice field.

Pete Bethune recounts his experience aboard the Japanese security vessel.

After months of frustration, Sea Shepherd finally find their target - the Nisshin Maru. Now, they must run an eight-mile gauntlet blocked by two harpoon ships aggressively defending their mother ship. The success of the campaign rides on this moment.

With three activists aboard the Japanese security vessel, Capt Paul Watson hopes the media frenzy will force the Shonan Maru 2 to back off. Meanwhile, the crew of the Steve Irwin are plunged into their most violent battle yet.

When a massive target is detected on their radar, Sea Shepherd sends out their new helicopter pilot to ID the mystery vessel. But as the helicopter reaches the limits of its fuel range, it abruptly disappears, crashing into radio silence.