The crews and battered boats are feeling the brunt of one of the hardest Opilio seasons on record. While some crew members battle potentially catastrophic breakdowns to stay on the grounds and keep fishing, others throw in the towel and call it quits.

The Cornelia Marie uses US satellites to spy on the Russians, Scott pioneers a dormant fishery and Wild Bill faces off with a Russian greenhorn.

When Sig and Mandy disagree on a fishing strategy, Clark is caught in the middle. Wild Bill comes down hard on deckhands as Linda gets too close to danger. Keith pulls the Wizard alongside the Saga and unleashes unexpected bad blood.

As wintry weather pounds the fleet, a 30-foot wave crushes a Titan Explorer deckhand, threatening Jake's captaincy. On the Time Bandit, Johnathan loses a generator and goes dark. The Aleutian Lady drives into the weather to reach Dutch Harbor for repairs.

Josh and Casey haul in their biggest pots ever, starting a gold rush to the Russian line. Captain Bill gets some inside intel, while Harvey confirms the numbers his own way. As Arctic Storm Elsa strengthens, the fleet realizes the ice queen casts a deadly spell.

Captains scramble to meet an expanded quota in the path of a violent system dubbed "Squall-pocalypse". A breakdown on the Wizard puts Monte in debt to the Time Bandit and Josh and Casey exceed their own quota when it comes to injuries on deck.

Saga loses a veteran deckhand, forcing Jake to steam a greenhorn army to the Russian line. Amid scuttlebutt that ports are closing due to a virus, Josh fights to get home for a reunion with his brother and Sig's daughter gets rushed to the hospital.

An early closure forces captains to work together to get their catch safely to port; Sig crosses a line when he repositions a rookie captain's pots; Jake and Sean race back from Adak while Linda bolsters her east coast reputation in the Bering Sea.

When Sig's fishing information falls into the wrong hands, he deals his protégé a lesson he won't soon forget. After his crew gets slammed by back-to-back waves, Rick faces a gun-shy deckhand. Sophia contends with a crewman with a badly infected tooth.

With unrelenting northerly winds bearing down on the fleet, every skipper steels himself for battle with the descending polar ice pack. And as temperatures drop on the grounds, tempers on deck flare up.

Two brothers find themselves in the same dire situation that sunk their father's boat. After a midseason hiatus, the fleet returns to the Bearing Sea, but the ice is back and worse than before. Now the skippers could get pushed past their breaking points.

Josh and Casey race to haul pots as engine failure threatens their delivery window. As seawater destroys his hydraulic motors, Junior attempts a risky high seas delivery of three new motors. Harley and his crew bang heads over his fishing strategy.

Sig and Mandy conspire to get Jake to do their prospecting, but the former deckhand seizes the moment to fill his own tanks. The Wizard crew must break through ice to rush Keith to a doctor. Junior fears the worst as a deckhand falls from the stack.

As a typhoon rocks the Bering Sea, the Summer Bay suffers a collision. Sig gambles all his pots in one spot, while Casey takes a scientific approach to finding the elusive Bairdi crab. John and Josh rush a pit stop to get the Time Bandit back in the hunt.

Sig gets tough news at sea forcing the Hansens to make a critical decision as John and Andy lend a hand. With wheelhouse ambitions, Jacob hits a wall with Keith on the Wizard. New captain Jack crosses a line when Harley makes a deal with Jake.

Sig buries his beloved mother and the last of his family's pioneering generation. Sean Dwyer joins forces with Rick Shelford but the two captains don't see eye to eye on rules. Jacob fights back on the Wizard and finds no safe harbor from Captain Keith.

A new deckhand falls ill on the Time Bandit, raising questions for Andy and warning signs for John. A bait pallet breaks loose, forcing Captain Rick to deal with a severe crew injury. When Wild Bill's plan A fails on the Summer Bay, Maria tries plan P.

In the winter season premiere, Sig and Keith risk fishing far from land despite a forecast Super El Niño season and encounter a gauntlet of Bering Sea weather. After sand fleas consume his bait, Johnathan strategically sets pots near a submarine volcano.

Aboard the Wizard, Keith must retrieve his lost anchor in 50-knot winds. Sig attempts a risky new strategy before finding himself racing to secure the next offload slot. Rick starts to turn his season around, only to lose a greenhorn to a gruesome injury.

John risks capsizing after being forced to fish with a slack tank. Jake hauls in the largest seas of his career. Under pressure to get home for the arrival of Mandy's second child, Sig and Clark fish deeper than ever before as mechanical problems mount.

Past the halfway point of the King Crab season, man and machine alike show signs of wear under the brutal hand of the Bering Sea. While repairs can be made to the equipment, the fishermen must dig deep to soldier on in a place where nature rules.

The polar ice pack invades the opilio crab grounds, forcing the captains to make a decision: grab their gear and run, or keep fishing and fight the floes. Two deckhands fall victim to an ice assault; a captain's troubles are compounded by a call home.

On the crowded blue crab grounds, a high seas showdown between the Saga and Seabrooke takes an unexpected turn. On the Northwestern, Captain Sig must make a tough decision about his brother’s future, while the Time Bandit has a close call in False Pass.

As King Crab season comes to an end, life-changing decisions must be made. The captains of the fleet pull up their last pots while young Jake Anderson struggles with his decision to leave the Northwestern, and Josh Harris plots to buy his father's old boat.

Atop the king crab super swarm, full pots boil over into conflict as young guns Sean and Jake join forces to set down Sig. Keith and Harley reignite a decades old rivalry, and Sean faces the long arm of Alaska law when crab in his tank come up short.