A great war called the Sixty Minute War caused horrific changes to the world's landscape resulting in near-constant natural disasters. In a distant future, people live in major cities modified with huge engines and traction-style wheels so that they can move everything rapidly to a safer area as disasters strike. The cities, known as Traction Cities, have also been designed to pick up other smaller cities and towns as they move so that their citizens can gather new resources. In areas of the world that refuse to give into this Municipal Darwinism, an Anti-Traction League does what it can to stop the cities. Tom Natsworthy, an apprentice in the Guild of Historians in the City of London, stops an attempted assassination against the guild's leader, Thaddeus Valentine, by a young woman with a scar on her face named Hester Shaw. This act of bravery nearly destroys Tom's life, but it leads him on an incredible journey that could result in salvation for the human race.