The race for untapped gold in bottomless depths kicks off as Chris and newcomer Joe go to war over a contested spot. Vern deploys an untested crew and new Nitrox air system for their deepest dives yet. Mr. Gold attempts to access riches via inland gold.

The first storm of summer arrives to rock the fleet; rivals Chris and Joe battle over big gold; Vern's diver faces a deep-water emergency; Kris orders the Mistress to put her crew on notice; Shawn makes a promising discovery.

After a week lost to stormy weather, the fleet scrambles to make up for lost time in innovative ways; Shawn employs a risky hydraulic blaster, Chris gambles on a rookie diver, and Joe pushes himself and his dive crew to dangerous levels.

Tensions rise as the mining season hits its midpoint; the Kellys launch the All-In and Zeke hits the cheese; Shawn struggles to find a pay streak and an alleged claim jumper sets up on the Tomcod Claim hotspot.

Tensions explode on the Tomcod Claim; Chris takes radical action against a dredge he believes is jumping his claim; when a massive explosion blows a hole in the Mistress, Kris scrambles to save his livelihood.

The fleet goes for broke as Kris launches his crawler deeper than anyone has ever mined. Shawn must haul massive, season-saving equipment through a rising river, and Chris makes a historic discovery: the biggest gold nugget ever found offshore from Nome!