Quintus, an Ephesian slave, is in attendance on his master, Sextus Julius Frontinus, the Roman governor of Britain, when Cunicatus, the chief of one of many warring tribes in ‘this hideous island at the edge of the world’, seals a marriage alliance between Frontinus and his daughter, Olwen. She, however, rejects the match, escaping from the camp at dead of night and impulsively asking Quintus to accompany her.