Joanna Lumley sets out to travel 6,400 miles making use of the Trans-Siberian Railway, which is considered the longest railway line in the world. Joanna's journey begins in Hong Kong, where she spent some of her childhood. She takes a bullet train to Beijing, where she meets a woman who claims to have known the last Chinese emperor's favourite concubine, and officially joins the Trans-Siberian track. From there, she travels to the Great Wall, and takes an overnight train into Mongolia via the Gobi desert.

In episode two, Joanna is in Mongolia and spends time with some Mongolian nomads, visits a giant statue of Genghis Khan and a gold mine. She spends time in the capital Ulan Bator where she tracks down the amazing Mongolian throat singers before catching the train to Putin's Russia. She meets Mongolian tradesmen on the train before crossing the border into Siberia.

In the final episode, Joanna is in deepest Siberia heading for Moscow, which she last visited in 1966. Her first stop is Lake Baikal, one of the deepest lakes in the world. She drinks vodka with a local fisherman before getting back on the train for Krasnoyarsk where she meets an oligarch. From there it's across the vast expanse of Siberia to Yekaterinburg, a city with a dark history. It is where the Russian Royal family were murdered. Joanna pushes on for Moscow, where she discovers a very different city from the one she saw in the sixties. She visits Stalin's nuclear bunker and encounters Russian models, before finding the place where she was photographed in 1966, which inspired the whole adventure.