Ewan and Charley are on the road to Kazakhstan. They notice how both the terrain and people have changed. At the border they are met by a welcoming committee. Almost immediately they encounter the horrible roads they've been dreading. Claudio (the cameraman) falls first. Later Ewan admits to being scared about falling off and nervous about the bad roads. The second greatest problem for Ewan and Charley are the constant police escorts: the last thing they want, they are quickly growing very tired of them. Another welcoming committee which although the guys appreciate, they want to be unfettered in their journey. A light moment filming a herd of giant woolly camels quickly turns heavy. A very rattled looking Ewan and Charley tell how a man in a car just pointed a gun at them. Another police escort takes the guys to a roadside turnout filled with more police cars and television cameras. Ewan is confused and upset. A policeman offers his house as a rest spot.

Before Ewan and Charley enter Mongolia, they have a small portion of Russia they must travel through first. They are thrilled to be on decent roads again, and make good time driving to Barnaul, a rather large Westernized city. Ewan and Charley are taken by surprise by the stunning gorgeous Altai region they find themselves in. There are literally no roads in Mongolia as we know them. Instead, the guys must follow tracks marked in the earth by trucks.

A bad fall and more mechanical trouble dogs Ewan McGregor and Charley Boorman as their motorbike odyssey continues. After regrouping to assess the damage, they head for Ulan Bator and are taken on an underground tour of the Mongolian capital's sewers. They then travel back into Russia and on to Siberia, where they're informed of a really bad stretch of road ahead. Reluctantly they decide to let a train take the strain.

Pushing on despite many setbacks, Ewan and Charley immerse themselves in the rich culture and their spirits are lifted by the beauty and kindness of the people of Mongolia. They know that the Road of Bones in Siberia (built by Stalin's prisoners) lies ahead and will surely test them further.

Ewan and Charley take in the wildlife in Alaska then head across the border into Canada and ride into the Yukon region. They meet the Firefighters tackling forest fires and a Welshman who takes them up in his aeroplane to view a glacier. After a visit to Calgary Funfair, Ewan is almost injured when a reckless driver causes a near fatal accident.