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.

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.

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.

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.

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.

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.

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.

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 strikes gold raiding Keith's hot spot, but when a line snarls his wheel, he must call his rival for help; a rogue wave knocks out Rick's electronics, forcing Bob to take the helm; Harley breaks in a new co-captain, only to break down at sea.

When the Time Bandit loses power with a storm at its tail, Johnathan deploys a camera probe to find what's snarling his propeller; Keith sets a decoy string to lure Sig away from good fishing, but risks his own secret plan by trusting the wrong ally.

In the winter premiere, the snow crab fishery reopens unexpectedly after three years; Keith and Jake charge north, only to collide with an incoming Siberian storm; Sig and Rick form a wary alliance, but with big money on the line, trust fails fast.

Winter season erupts as the fleet battles brutal seas and each other. Sig and Rick's alliance shatters as Keith fights through a debilitating injury and a short-handed crew. The Titan Explorer loses steering in heavy seas, leaving Jake dead in the water.

Venturing 600 miles north, the fleet encounters subzero temperatures and freezing spray. Sig sets into a tidal surge, but the extreme forces leave Clark injured. While Keith fishes through pain, Jake's risky pact unravels when a key man goes down.

Keith & Jake deploy guerrilla tactics when a factory trawler invades their grounds. At the Russian Line, Rick encounters temperatures so frigid that even snow crab can't survive on deck. Sig struggles against mounting breakdowns threatening his delivery.

After six relentless weeks at sea, man and machine push past the breaking point. While Keith seeks medical care in Anchorage, the Wizard loses steering in 20-foot seas. Rick fears the worst as he takes on water, and Clark finds Sig unconscious below deck.

As buyers close their doors, the fleet scrambles to collect its first opilio windfall in three years. After Sig's collapse, Clark assumes the full skipper role. Keith returns with a million-dollar vengeance, while rogue waves threaten Jake's operation.