The Victoria Diggers suspect that all the gold from the mine shafts they're excavating has already been cleaned out, and Jake's new 'vat leaching' plant delivers a 100-ounce motherlode.

As the end of the season approaches, the Scrappers are over $185,000 short of target, the Dirt Dogs' season is on the ropes, and the Victoria Diggers' job becomes dangerous as a heavy storm strikes.

The Dirt Dogs' massive dry blower shuts down due to extreme 50-degree Celsius temperatures and the Mahoneys and Gold Gypsies take a last-minute gamble that delivers big gold.

Neville and Mick's final hunt of the season is set to deliver another monster nugget; Dirt Dogs' Jake secures a last-minute deal; Scrapper Alex pays the ultimate price for gambling his life savings.

In the Swiss Alps, engineers battle extreme heights, brutal weather and near-vertical terrain to build a record-breaking mountain cableway to the summit of Schilthorn.

In Poland, engineers battle unstable mountains, methane gas and treacherous terrain to build a new high-speed railway through the Carpathian foothills.

In Colorado, engineers battle drought, extreme weather and immense water pressure to raise a 70-year-old dam to record-breaking heights.

Dale's business is growing, but so are the risks. A cliffside wreck recovery forces him to face fears and prove he's up to the challenge.

Snow, ice, and a deadly mountain road push Dale to the edge as he fights to stay in control and keep his business moving forward.

Bryce races out early. Myles tops the tally-board and Jack remains grounded. A mystery skipper enters the picture.

Jack makes it out to sea. The rest of the fleet are hunting in deep water. Bryce's antics are causing tempers to fray.

Bryce pranks a superstitious Squizzy. Myles is under attack from Sea Lice and Jack hits a rock and is in deep trouble.

Myles has a deckhand decision to make. Bryce rockets up the tally-board and Squizzy heads to the casino in the sea.

Myles and Timmy are at breaking point. Squizzy's risky gamble pays-off and Bryce rockets to the top of the tally-board.

The Gold Devils race against the elements, Jacqui and Andrew push to new extremes, and mechanical issues leave the Ferals divided.

Alan and Salty hit a dead end in the remote Kimberley region, Vince, Bibi and Murray are forced to break new ground in Victoria, and the Gold Retrievers struggle with their misfiring wet plant.

The Gold Devils battle on after losing a team member, the Ferals' nugget trail goes cold, and Jacqui and Andrew face a night-time detecting mission for lost gold.

The Gold Devils gamble on a potential motherlode, Alan and Salty go offroad in the extreme wilderness of the Kimberley, and Shane and Kate try to get two wet plants going but run out of water.

The Poseidon Crew are forced back onto an old lease in flooded Victoria, Shane and Kate call in help in Western Australia, and Jacqui and Andrew get separated at night in far north Queensland.

The Arctic's late freeze presents unique challenges for Alaskans as they attempt to gather food and resources for survival.

Repairs, hunting and errands are all on the to-do list as five Alaskans struggle to get through the everyday grind as the long, dark winter looms ahead.

An early kick off to the winter fishing season on Lake Winnipeg as temperatures plunge and the Ice Viking fishing crews scramble to get onto the ice with their nets.

The temperature drops as the fishing crews continue targeting the most valuable fish possible. But as the lake ice locks into place, it presents a whole new set of challenges.

Chris Kristjanson receives delivery of his dad's new lifting caboose, but he is reluctant to use it. Meanwhile, the Husavik Crew faces frustration as they are unable to bring in the catch they need.