The Last Legion tells the story behind the legend of King Arthur. It follows Romulus Augustus, the last emperor of Rome, who is exiled as a child. Romulus and his tutor Ambrosinus escape to Britain to search for the Ninth Legion. They help the Romans defeat invading barbarians in battle. To honor the fallen soldiers, Romulus drives a sword into a rock. Years later, Ambrosinus, known as Merlin, takes a young boy named Arthur to see the battlefield. He reveals that Romulus married Mira and ruled wisely as "Pendragon", and that Arthur is Romulus's son. The film shows the sword exhumed from the stone, with the letters slowly emerging to spell "