Mosley traces the turbulent political career and tempestuous private life of Oswald 'Tom' Mosley, leader of the British Union of Fascists during the 1930s. Over four episodes the series charts Mosley's rise to political notoriety through his personal life– from youthful rising star of the Conservative Party to potential leader of the Labour Party, and later abandonment of conventional party politics to become a figurehead of burgeoning fascism.