The crabs have vanished, which ignites a grueling hunt to save the fleet's way of life. Captain Sig returns to the helm after a major heart attack. Wild Bill debuts his own brand new boat in a crisis season. A rescue is attempted for a heart attack victim.

The fall season begins with some uncertainty. A seismic shift in sea temperature sends the fleet searching for displaced crab and then they must fight through an unseasonably large first storm.

Rising sea temperatures test the fleet. Toxic smoke engulfs the Saga. Sean struggles to save the family business on the Brenna A. Wild Bill fears he could lose Nick to a terminal illness.

Wild Bill uncovers the truth about Nick McGlashan's terminal illness. A damaging mechanical issue threatens to crush Jake's future. Warming seas force Keith into the unknown.

Johnathan and Andy Hillstrand fish together for the last time. Keith's inattentive crew sends the Wizard on a collision course. A belligerent deckhand tests Jake's resolve as captain.

A big decision weighs on Sig Hansen. Rookie captain Sean Dwyer gambles on a new venture with a new crew. Jake Anderson struggles to replace a lost anchor before his quota is taken away.

The last moments of the fall season bring its biggest storm. Wild Bill struggles to pilot his new boat in big seas. Johnathan faces off with a massive swell in the perilous False Pass.

Competition doubles when the quota is cut in half. Three captains arrive early for the winter season, but Johnathan goes one step further and plots a dangerous, 600-mile course to Russia.

Sig returns to the season that nearly killed him. After a tough start, Keith and son struggle to prove themselves. Wild Bill gives Nick McGlashan a second chance. Jake lets go of a friend.

When the Arctic opens up its winter wrath, the first of multiple back-to-back hurricanes descend on the fleet. Spotty fishing and mutiny also converge to create the perfect storm.

An Arctic mega-storm rocks the fleet. Sig plays cat-and-mouse with towering waves. Keith watches an 800-pound crab pot launch into a deckhand's spine. Wild Bill fights for a comeback.

Sig's stress takes a toll. Sean tries to dock in a hurricane. Keith is left dead-stick in massive seas. Jake motivates a defiant hand. Johnathan rolls the dice by Russia.

Sig, Johnathan and Jake attempt to run from a second arctic hurricane, but Keith refuses to heed the warnings. Stress-induced chest pains threaten the remainder of Sig's season.

After suffering chest pains, Sig awaits news in the hospital. Wild Bill struggles to stay out of harm's way while also handling dissention on deck. Sean lays down the law with Zack.

Sean is set on a collision course with another boat, two deckhands get taken down on the Wizard, and Jake almost loses a deckhand.

Two old friends race to finish their seasons, but one hopes to cap a storied career; Johnathan Hillstrand wants to bid farewell in a blaze of glory.

The U.S. Coast Guard desperately scours the Bering Sea for a missing crab vessel, while the fleet anxiously waits to discover the fate of its six-man crew. After a plea from his wife, Sig contemplates an early exit.

In the wake of the Destination tragedy one last storm bears down on Edgar, Bill, Sean and Jake. The Coast Guard attempts to save the crew of a fishing vessel while their boat is taking on water.