Comedians Rhod Gilbert and Greg Davies attempt to drive through the mountainous, landlocked nation of Nepal. Starting from the chaotic border with India, they travel across the country's most important roads.

Ben Fogle and Hugh Dennis travel from the Peruvian Andes to the depths of the Amazon, in search of the lost city of Constitucion.

Ed Byrne and Andy Parsons brave temperatures as low as minus 50 to drive across Siberia's infamous Road of Bones. Along the way they encounter all that Siberia can throw at them from terrifying roads of ice and deserted gulags, to the surprising welcome of the people who inhabit this freezing wilderness.

Sue Perkins and Liza Tarbuck drive the legendary Ho Chi Minh Trail, a network of dangerous roads hacked through mountains and jungles of Laos and Vietnam. Its role in the Vietnam War has left it one of the most perilous roads in the world as it is littered with unexploded bombs. Sue and Liza face a gruelling drive to some of the least explored sections of the trail.