A cracked tank on the Titan Explorer leaves Jake's engines vulnerable to seawater. Keith fires another deckhand but struggles to get rid of him for good. Johnathan prescribes alternative cures as the norovirus overtakes the Time Bandit crew at sea.

Sig must act quickly as heavy ice entombs the Northwestern. When Keith's Australian greenhorn challenges his old-school command, a culture clash erupts. Hellbent on earning an ownership stake in the Titan, Jake hauls pots at a blistering pace.

Johnathan's dash to the dock halts as the Coast Guard boards the Time Bandit. Sig seeks a bigger biomass out west and convinces Rick to go to Adak to dig up his father's lost fishing spots. The Hillstrands attempt a high-risk harbor entry in 20-foot seas.

In treacherous western waters, Sig and Jake gamble on a daring new fishing strategy. Rick and Sophia attempt a perilous boat-to-boat transfer to save a quarter of a million dollars of crab. The fleet mourns the loss of beloved fisherman Nick Mavar.

A brutal knife injury on the Northwestern leaves Sig scrambling. After one crewman quits, tensions explode on the Confidence until even the co-captain revolts. The Wizard faces a nightmarish mechanical failure when Keith's throttle fails in rough seas.

A typhoon brings monstrous waves and high winds to the west. Rick and Bob attempt to stitch a head wound in turbulent seas, while John risks capsize to make a harbor entrance. An emergency tests Jake between his duties as captain and man of the house.

After a deadly chemical leak forces Jake to abandon ship, Keith races to locate the Titan Explorer crew and save their ailing vessel. With Sig aboard the Time Bandit, Mandy takes the Northwestern's helm for her first-ever solo king crab season.

Captain Sig faces the choice of a lifetime -- hunt king crab on traditional grounds, or risk it all by chasing whispers of monster king crab in the west. The rumored billion-dollar bounty lures captains and crews to venture beyond the bounds of rescue.

In the Season 21 premiere, Sig and Johnathan head to abandoned Adak Island, chasing rumors of giant king crab. Co-captaining the Time Bandit, the two legends spark a gold rush out west, until chaos on the Titan Explorer forces Jake's crew to abandon ship.