Tom (Robert Sheehan) is a sixteen-year-old Londoner who has only ever lived inside his travelling hometown, and his feet have never touched grass, mud or land. His first taste of the outside comes quite abruptly: Tom gets in the way of an attempt by the masked Hester (Hera Hilmar) to kill Thaddeus Valentine (Hugo Weaving), a powerful man she blames for her mother’s murder, and both Hester and Tom end up thrown out of the moving "traction" city, to fend for themselves.