Newcomer Ken Kerr and the 600-ton beast Myrtle Irene threaten Shawn's plan to build his megadredge; the elements jeopardize Emily's plan to dive deeper; Kris heads to The Bluff with a new dredge, but faces complications.

Dangers rise with the tide; Shawn has a mishap underwater; Emily faces a possible collision; George prospects for brother Dave; Ken Kerr and the Kellys take home a chunk of gold.

Shawn and Kris battle encroaching miners; Ken's beastly Myrtle Irene continues to invade and operating costs soar; Emily expands her operation, but an air malfunction threatens her season.

In the Bluff's lawless waters, Shawn and Kris wield brute strength and make verbal threats while standing their ground against the competition; in Nome, Alaska, Emily and George gamble on new strategies and resources.

The approach of a unhappy storm pits safety against the drive to succeed; Ken rushes to free the Myrtle before it's destroyed; Kris risks being stranded; Shawn mines until the Bering Sea rips up his dredge; Emily attempts to appease nature.

A unhappy midsummer storm forces the fleet off the mining grounds. Shawn, Ken, Emily and Kris race to repair and improve their dredges for an end of season attack while reliving some of their most dangerous and triumphant moments on the Bering Sea.

The Bering Sea battle heats up as Shawn bets big on a new discovery he hopes will keep him ahead of Ken's massive dredge; the Kellys are forced to find new ground; Emily nearly boils a diver alive.

Shawn works overtime to cover for his exhausted crew; Kris is blind-sided by the loss of his lead diver; Emily jumps in to prevent a fuel spill; Ken and George collaborate to find Myrtle a mother lode.

Winter winds force the captains to reevaluate risk and reward; Shawn's mega-barge extraction takes a turn for the worse; Ken pushes the Myrtle to the limit on a five-day run; Emily sends her divers deeper; Kris invents a new form of prospecting.

In a race against winter, Shawn extends his sluice to get more gold; Ken pushes the Myrtle 24 hours a day; Emily tangles with the tide; Kris battles a bed of quartz; George enjoys a season-ending dive with his son.

Desperate to be Nome's gold king, Shawn risks the Christine Rose in dangerous waters. Ken struggles to free the Myrtle from the harbor. Emily fights a fouled airline and Kris attempts one more dive at the Bluff.

In a shocking confrontation, Nome's top two miners Shawn and Ken come face to face after a season of squaring off, having revolutionized mining with bigger, badder, gold-grabbing machines; secrets are revealed through never-before-seen footage.