Four friends set out on a gruelling jungle expedition to investigate rumours of Golden Dorado following migrating baitfish up an uncharted Bolivian river.

The guys head deep into Zambia, chasing reports of Tigerfish. Standing in their way is 400 miles of unpaved roads, crocs, hippos and a serious lack of fuel.

The crew is in Mongolia in search of taimen: the largest, most ferocious member of the salmon family. To get there, they must navigate treacherous conditions.

The guys are in Borneo, looking for a fish close to extinction, the mahseer. To find it, they risk entering the territory of the headhunting Dayak people.

The team follows a lead to a remote river in Greenland, believed to hold huge Arctic char. And, they investigate a myth of Atlantic Salmon occupying a lone river.

The crew travels to Australia where guides take them way off the grid to a fisherman's paradise in search of barramundi.