A freak accident strikes the Northwestern with Mandy alone at the helm. Josh charts a new course on the Cornelia Marie while Casey sleeps. Lights go out on the Wizard, and Harley's launcher snaps at the worst moment.

The Bering Sea takes a toll on captains and crew. Wild Bill calls the Cornelia for help. Jake confronts a disorderly crew, forcing his toughest decision yet as captain. Josh mans the helm as Casey makes a risky ship-to-ship transfer in high seas.

Josh and Casey risk a 500 mile trek north to the icy Russian line. Jake tracks his own fast-moving crab horde. Sig does double duty on the Northwestern. The Bering sea cracks the Wizard's steel hull as the Colburns face the loss of their dad.

As the crab become harder to find, veterans Sig Hansen and "Harley" Davidson form an unusual alliance, however trust doesn't come easy for old school captains. Freddy pays a price for Keith's decision to haul in rough seas and Jake tempts fate to become a boat owner.

The bone-breaking winter unleashes fury on the Summer Bay. A rookie mistake leaves Captain Bill short a hand. Jake hits the jackpot at sea, but forces on land cost him dearly. There's hell to pay when Sean discovers the fatal flaw in his crab count.

In the biggest storm of the season, Jake faces a life-or-death decision when a shifting stack threatens to capsize the Saga. Sig and Mandy haul through angry seas, while Josh and Casey gamble on quota but find there's more on the line than numbers.

As winter intensifies, Sean faces an engine room fire. Summer Bay deck boss suffers a season-threatening injury. Harley offers a newfound nephew a trial run at greenhorn. Monte races to fill Wizard's quota so Keith can say farewell to their father.

Deckhands pay in blood as captains make up for time lost to the storm; on the Cornelia Marie, Josh takes the wheel as Casey conducts surgery at sea; Brenna A tests the mettle of a former Marine; a call from home has Sig facing a worst-case scenario.

The fleet battles a freight train of back to back storms. Sig's crew pays a price for some stuffed pots and Harley risks his gear to cash in on an elusive crab hoard under the ice. Freddy attempts to perform self surgery on the Wizard and on the Summer Bay the crew gets news on Nick's future.

As smoke starts to fill the Wizard, Keith and Monte face a dark ship nightmare. Massive breakers shatter Jake's steel anchor forcing him to fight to avoid the rocks of St. Paul Island. Battered by relentless seas, Sig turns to his family to fill the Northwestern's tanks.

Each captain’s next move determines who survives the final winter push. Winds put the Wizard on a collision course with a monster wave. Jake taps a Hillstrand to save the Saga. Josh and Casey hit numbers not seen since Josh’s father, Phil Harris, was captain of the Corneila Marie.

The coldest weather in nearly a decade threatens to crush hulls and freeze the sea. Monte must fill his tanks fast to get home to his ailing father, while a shocking mishap leaves a Hansen family member grasping for life.

In the season finale, with just ten pots to go, a crushing injury requires Coast Guard rescue. Josh and Casey face a huge loss when their offload gets cancelled. Sig gambles on an early finish, while Monte hauls more crab than the Wizard can hold.

The wrath of Arctic Storm Elsa hits the Cornelia hardest as a breakaway pot thrashes Josh and Casey's crew; Capt. Keith orders deckhands onto the stack as Elsa's icy blasts threaten to capsize the Wizard; the Saga takes a rogue wave.

As arctic super-storm Elsa intensifies, a forecast warns of isolated waves of unusual size; trapped in the crab-rich northern grounds, the Cornelia Marie, Wizard and Southern Wind haul pots as big as the waves, until one boat faces a 60-foot monster.

Monte returns to co-captain the Wizard just as massive storms slam the fleet from the south. Jake risks hauling his pots in 30 foot seas to return to his family. Wild Bill goes farther north into the icy Arctic than any other boat in the fleet.

Hours before king season, a huge new boat with a renegade captain finds the crab are all in one spot. The fleet races to find the hoard and fight for their share.

In storm-driven seas, Cornelia Marie's crane goes off the rails; Sig risks navigating a rocky passage in treacherous conditions, and the Wizard crew face a rogue wave without warning.

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.

In storm-driven seas, Cornelia Marie's crane goes off the rails, smashing Josh and Casey's wheelhouse and injuring deckhand Taylor; Sig risks navigating a rocky passage in treacherous conditions, and the Wizard crew face a rogue wave without warning.

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.