AD 117. The Roman Empire stretches from Egypt to Spain, and East as far as the Black Sea. But in northern Britain, the relentless onslaught of conquest has ground to a halt in face of the guerrilla tactics of an elusive enemy: the savage and terrifying Picts. Quintus Dias (Fassbender), sole survivor of a Pictish raid on a Roman frontier fort, marches north with General Virilus' (West) legendary Ninth Legion, under orders to wipe the Picts from the face of the earth and destroy their leader Gorlacon.