The Scrappers are on the hunt in order to keep their wash plant pushing out gold, Rick struggles with 45-degree heat, and Greg rushes to the other side of Australia to be at his ill father's bedside.

The Gold Gypsies are at breaking point when they discover signs of poachers stealing gold, the Scrappers are still chasing over 62 ounces, and Rod and Eric try to repair a broken conveyor roller.

The Scrappers are just over halfway to their target but bleeding money; the Gold Gypsies are desperate to find their final 30 ounces; the Mahoneys return to their 8-Mile lease earlier in the season.

The Dirt Dogs' one-million dollar target looks like a far-fetched dream; the Mahoneys are over $22,000 of gold short of their target; Rick is close, but finding that final $1,600 of gold is tough.

The Integrated single stem logging team tackles steep ground and climbs some of the tallest trees in the British Columbian wilderness, and Duz Cho Logging is rocked by an unexpected snowstorm.

A rotten bridge forces the Freya crew to move to another section of the block, and the Peters crew is on track to finish Statlu by the end of a day when an operator error threatens to shut them down.

The Integrated single stem crew fight to finish The Drop as the wind and fog fight back, and the Peters crew suffer a huge mechanical malfunction that could ruin their plans.

In the United Kingdom, engineers battle tight deadlines, complex terrain and live infrastructure to build HS2 - a record-breaking high-speed railway linking London and Birmingham.

In Denmark, engineers battle icy seas, powerful currents and punishing deadlines to build a four-kilometer-long mega bridge that will form part of a major new European transport link.

Captained by Bruce, the Wildcard crew targets 45 tonnes of mackerel in four months; bad weather, engine trouble and sharks threaten their season, but a lucky streak might just save the day.

As the Wildcard crew prepare for their first unload of the season, Prue and three-year-old daughter Ellica find themselves out at sea and face to face with a hungry shark.

Six weeks into the mackerel season, the Wildcard crew faces incredible highs and lows; a record haul brings triumph, but injuries, tensions, sharks and a sinking rowboat could threaten it all.

The Wildcard crew heads to a risky fishing spot known for sharks, a gamble that puts their season target in jeopardy; with tensions high, pregnant Jess faces a terrifying challenge.

The crew's luck runs out after an amazing haul as Bruce boldly decides to steer to Cape Carnage; just as the move starts to pay off, devastating news bring their success to a halt.

The Gold Devils set their sights on a record-breaking total, and a gold drought causes one member of the Poseidon Crew to question his future.

The Gold Devils move their multi-million-dollar operation in search of big gold, and the new team of Vince, Bibi and Murray break ground on their dream lease.

The Ferals are on the gold when a four-wheeler crash leaves them a man down, and the Poseidon Crew battle to overcome a catastrophic mechanical failure.

The Gold Devils pin their hopes on an exploration mission to a rugged outback lease, and flood waters wreck the Gold Retrievers' new plant.

The Ferals lose a team member in the unforgiving outback, and Shane gets an attractive offer that could break up his partnership with Russell.

As winter approaches, the Hailstone family receive news of some land they have inherited. Meanwhile, after being stranded for days, Glenn attempts to return to his remote cabin.

A power outage in Kavik leaves Sue Aikens scrambling to restore her communications, while Glenn Villeneuve sets out on his most crucial hunt of the year.

A team in Labrador race to install a bridge across a massive gap in the sea ice, and a vessel sails into St John's with over 30 million dollars in cargo.

Hundreds of skippers prepare to launch for their biggest fisheries, but an ongoing shore-side debate threatens to halt everyone's livelihoods.

Veteran skippers hustle to maximise crab season while as researchers work quickly to stop the spread of an invasive species that threatens marine life across the island.