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.

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

Captain Watson is in pursuit of the Nisshin Maru when all three Japanese harpoon ships suddenly appear on out of the fog. The Sea Shepherds are completely outnumbered.

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.

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

The Sea Shepherds kickoff their 10th anti-whaling campaign in the Antarctic (Operation Relentless). As the long range icebreaker Bob Barker gets underway, Captain Peter Hammarstedt knows that the Japanese whalers most likely will be more aggressive than ever (he reflects on last year's campaign, Operation Zero Tolerance, when on February 20th, 2013, the Nisshin Maru rammed the Bob Barker and nearly capsized it while attempting to refuel from its bunker ship, the Sun Laurel). But this year, the Sea Shepherds are going on this campaign without their founder, Captain Paul Watson (who's back on land in an undisclosed location). So leading this campaign will be Captain Peter Hammarstedt, while Captain Sid Chakravarty commands the Steve Irwin, and commanding the Sam Simon is an American, Adam Meyerson. The Steve Irwin and Bob Barker will be patroling in the Ross Sea (Captain Peter is taking a gamble that the whalers will only be in this area and avoid Australia-Antarctic territorial waters because at the same time the campaign is going on, the International Court of Justice is reviewing an action against the Japanese whalers by the Australian government, challenging the claim that the whalers are doing scientific research), while the Sam Simon during this campaign will remain in a holding pattern 400 miles due north of Ross Sea acting as a refueling vessel. Three days into the whaling season, the Steve Irwin's new helicopter nicknamed "Sea Wasp", spots the factory ship Nisshin Maru and one of the three Yushin Maru harpoon ships. Unfortunately, the Nisshin's flensing deck is covered in red and has three minke whales on its deck, meaning four whales are dead. The Bob Barker is only 30 miles away and immediately heads for the factory ship as the helicopter heads back to the Steve Irwin. But in his rush, Captain Peter pushes the Barker's aging engine beyond its limits, and is forced to stop down as the Nisshin gets away. Meanwhile, the Irwin encounters the security ship Shonan Maru No.2 (the same ship that rammed the speedboat Ady Gil four years earlier). The small boats Delta and Humber engage the Shonan by first trying to plug the water cooling vents, but that doesn't work. So they drop prop fouler lines and stop the Shonan, allowing the Irwin to escape.

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.

Season Finale.The Sea Shepherds continue to attempt to disrupt the whaling fleet's operations. When the Yushin 3 tries to transfer a dead whale to the Nisshin Maru, Captain Watson maneuvers his ship to block the transfer resulting in a full-speed collision.

The series starts with a dramatic encounter with the Japanese Whaling fleet. The episode then flashes back to the maiden launching and departure of the vessel from homeport three months earlier. Paul Watson and the Sea Shepherds head back down to Antarctica for what promises to be their most intense anti-whaling campaign yet. However, no sooner does the ship leave port than the ship's Gyro breaks and they hit a massive storm the size of Australia

As the Sea Shepherds prepare for their fourth straight day of engagement with the Japanese whaling fleet, Andy and Simon argue with Dan over the best strategy for attack.

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.

The Sea Shepherds face a difficult 2013 campaign with the Brigitte Bardot and their helicopter unavailable. The fleet introduces a new ship, the Sam Simon. Former captain of the Steve Irwin, Paul Watson, is forced to step down due to an injunction preventing him from coming within 500 yards of Japanese whaling fleet. All four of the fleet's main ships feature a new captain, with Watson serving as an observer. The Steve Irwin remains to coordinate the operation. The Bob Barker is sent to search for the whaling fleet and finally locates the Nisshin Maru near the western edge of the whaling ground. However, they sit helplessly as the Japanese successfully kill and load a whale onto the factory ship. The Sam Simon is sent to search for the bunker ship Sun Laurel and finally locates it along with 2 Japanese whaling ships. They attempt to block the refueling, but fail when the rookie captain pulls away, not willing to risk his crew. After hunting, the Nisshin Maru turns east. Realizing that the factory ship is trying to also refuel, the Sea Shepherds send all their ships to interfere. 30 hours later, the ships prepare for the showdown. The 500-tons Bob Barker blocks the 5000-tons Nisshin Maru by parking right next to the Sun Laurel. The Japanese warns the Bob Barker to move but captain Peter Hammarstedt refuses to comply. The Nisshin Maru then pushes the Bob Barker with their bow, damaging the ship and causing it to list dangerously. After a standoff, the Nisshin Maru backs away while the Sun Laurel abandons the operation. Days later, the whaling fleet leaves for Japan with only 103 kills.

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 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.

A huge weather system moves in and the Steve Irwin is forced to take shelter behind a large iceberg. By morning, they are surrounded by ice so thick they can no longer move. The ice begins to push against the aging ship's fragile hull, denting it inwards.

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.

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 depart on their 2010/2011 ant-whaling campaign with a new, fast interceptor vessel. Early on, they find two harpoon ships before the whaling fleet has killed a single whale. Could they be set up for their most successful campaign ever?

When damage happens to one of the small boats, and the Bob Barker is five hours away, the crew realizes that they will have to spend a night at sea. But the crew is wet and freezing already, and early symptoms of hypothermia begin to set in.

New Zealand's Navy contacts the Steve Irwin to respond to an emergency distress signal where five crew members from a Norwegian sailboat have gone missing. Now the Sea Shepherds must risk their lives in a dangerous mission to find the missing mariners.

In the fourth-season finale, Watson claims a major victory after 30 years of fighting, while he and the crew reaffirm their commitment to stopping the whaling fleet.

A plan to intercept the whaling fleet before it reaches the whaling grounds is nearing a critical point. The new helicopter pilot, Gary, spots a ship on the horizon; If it is the whalers' factory ship, this may be Sea Sheparhd's the earliest victory ever.

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.

The Steve Irwin is quarantined in Hobart and the crew anxiously waits to find out if they have been exposed to Anthrax. Finally they get the all clear and 1st mate Peter Brown wastes no time leaving the ship after having quit the campaign.

Surrounded by the Japanese whaling fleet, the Sea Shepherds ready themselves for their biggest day of battle to date on the campaign. Helicopter pilot Chris flies up and confirms the crew's fears - all of the whaling vessels are equipped with LRAD weapons.