Young mining gangster Chris McCully challenges Mr. Gold's dominance.

Innovative mining strategies pay off for Chris and Shawn.

Chris McCully continues to pose a serious threat to Mr. Gold. Vernon and crew are plagued by mishaps. The Kellys wait for a game-changing piece of gold mining equipment to arrive. Shawn competes in Nome's biggest snowmobile race.

Shawn and Zeke each risk dangerous ice missions in the hopes of big paystreaks. Kris' gold mining miracle has arrived but requires some assembly. Jane does her best with an absent Emily and a diver who can't swim.

Chris finds himself stranded on the ice. Shawn hits a mysterious dry spell. The Kellys' brand-new Crawler awakens but encounters electrical problems. A tangled tether spells bad news for Zeke and the boys. Vernon finds two divers are better than one.

The Kellys unveil their secret gold mining weapon. Chris McCully's hot paystreak continues. A scary close call forces Zeke to adjust strategy. Jane butts heads with her crew as tensions boil over. Shawn discovers a hidden treasure at the bottom of the Bering Sea.

Jane clashes with Emily's crew over being disrespected. Equipment failures cause delays for Chris and Shawn. Kris is thrilled to find his Crawler in action. Pressure ridges cause one close call too many for Zeke and his crew.

The Kellys quarrel while trying to make their gold-sucking Crawler work. Some anatomical-looking worms in the sea may lead Shawn to gold. Vernon's best laid plans falter as he deals with health issues. Jane receives news of the birth of Emily's baby.

Mr. Gold and Chris McCully battle it out for the top spot on the gold board. The Kellys are at risk of ending the season with no gold. After some dangerous dives, Jane, Vernon and Zeke's crews each make a push to finish the season with a bang.