Michael Portillo continues his 1,000-mile journey from the northern state of Minnesota to the home of the blues in Memphis, Tennessee. In the nation's rail capital, where tracks pass underground and over ground and are elevated into the air, he investigates the ultimate marshalling yard. At the ornate Palmer House Hotel, Michael recreates the original chocolate brownie, invented by Bertha Palmer in 1893. He discovers the origins of the Sanitary and Ship Canal and uncovers the history of an incredible civil engineering project which raised the city to new heights. Heading deep underground, Michael inspects a modern-day scheme on a similarly awesome scale, described by the boss as the largest toilet in the world!

On the trail of one of America's most famous railroad names, Michael heads south to Pullman to investigate the legacy of its founder, George Pullman. Beside the Kankakee River, Michael is invited to visit the Frank Lloyd Wright-designed house that changed the face of American architecture. On the platform at Kankakee station, Michael parties with the locals as they celebrate the City of New Orleans rail service, immortalised in song by Arlo Guthrie. He gets his hands on a vintage hooter riding on the Monticello Heritage rail line and in Champaign learns a thing or two at a railroad university.