Summer temperatures at an all time high disrupt the seafloor, causing miners to find new strategies. Shawn fights a legal battle. Ken tries to keep his gold crown, while Emily and the Kellys look to expand their operations.

As summer kicks into gear, Ken and the Myrtle Irene get stuck in the mud. The Kellys are forced to bail out at Fort Davis. Elaine tries to make up for lost time due to Vernon's late start. And Shawn receives word on the fate of the Christine Rose.

Shawn gets his first taste of the shifting seabed. Ken tries a new perspective to find new ground. Kris and Emily each try out greenhorn divers to boost their productivity, but the plan grinds to a halt for one of them.

As the miners look to find more valuable ground, Shawn must fight the sea's shifting tide, Ken strains his excavator arm when digging hard cobble, Kris tries his chances with a rookie diver and new diver Brian saves Vernon's day.

Tensions fly as Brad leads The Reaper into hostile waters where Emily defends Claim 14 from claim jumpers. Shawn hunts an elusive pay-streak. Ken puts a risky Myrtle Irene repair to the test.

Shawn's rocky pay-streak takes him for a wild ride. Kris raids another claim but a rival dredge fights back. Vernon loses patience with his crew's performance. Ken tests a new operator to keep running around the clock.

After the raging storm, Ken learns the Myrtle Irene's fate. Shawn uses a new tool to hunt for new hotspots. Emily brings on a new crew member from her past. Vernon tries his luck at river mining. Kris gambles on an alliance to turn his season around.

Shawn confronts his dad for the sake of the family operation to disastrous results. Emily brings her father aboard The Eroica.

As summer’s end approaches, Shawn claws his way closer to the top of the gold count. Emily leaves her unpredictable father to tend on the Eroica. Kris works his new partnership in pursuit of a brighter future. And Ken pushes the repaired Myrtle Irene.

Kris mines an undersea trench, but a cave-in of rocks threatens his life, pinning him to the seafloor. Desperate to find a patch of career-saving gold, Shawn follows a hunch to deeper ground.

In the midst of the season-ending storm, Emily plays chicken with Mother Nature, but may lose her diver in the process. Ken pushes the Myrtle to its max. Elaine proves herself to Vern by calling the shots.

Winter has come -- along with the thinnest, most unpredictable ice in decades. After three years, Shawn returns to diving under the ice in pursuit of the Tomcod claim. Kris tries to set up and mine in one day. Emily's dependable Claim 14 shocks her.

Only days into the winter mining season, a regulator freeze up cuts off Shawn's air supply. Emily negotiates with Mr. Gold for season-saving coordinates. Vernon returns to the ice with an eye to buy Claim 16. The Kellys get on some gold.

The clock ticks as an impending arctic storm gathers strength; Shawn can't quit the gold; Kris gambles on another rookie miner; Emily finds gold but her equipment fails; Vernon risks everything to test Claim 16.

Following the arctic storm that drove everyone to shore; Shawn embarks on a marathon dive; Kris unveils a diving relay with The Reaper's new diver Shaunna; Emily takes another desperate shot at TOMCOD gold.

Suffering the icy burn of possible defeat, Kris wrecks his 3-diver relay plan and abandons his crew. Shawn is forced to question TOMCOD. Emily returns home to Claim 14. Vernon gambles on the edge of the ice.

Shawn races to prove the viability of the TOMCOD; Kris makes amends with his crew; Brad dives for the first time in five years; Emily tries to break her ice season curse.

When the temperature plummets to a season low, Shawn fights frozen ground with steam heat. Kris' hot plan to beat the cold fizzles quickly. Vernon gambles on a new spot.

As an arctic blizzard wreaks havoc across Nome; Kris finds gold under the ice, but fire erupts overhead; Shawn struggles to rescue his operation; Emily risks it all on a double dive; Vernon leans on a diver making her comeback.

On this ice season Judgement Day, Shawn pushes himself and his equipment to the edge. Kris and the Kellys rise from the ashes of an engine shack fire. Vernon pitches his operation to a big time investor.

As the miners rush to solid ground before the ice vanishes, Mr. Gold outlasts the fleet to secure TOMCOD. Kris assembles a makeshift operation. Emily rolls the dice on one last dive and Vernon hightails it to land on dangerous ice.