An English knight of chivalry, Bowen, mentors a Saxons prince named Einon, in his ideals with the hope that he will be a better king than his tyrannical father King Freyne. While suppressing a peasant rebellion, the king is killed and Kara, a young peasant girl, accidentally causes Einon to be mortally wounded. Einon's Celts mother, Queen Aislinn, has him taken before a dragon and asks it to save the boy's life. The dragon replaces Einon's wounded heart with half of its own on the promise that Einon will rule with justice and virtue. However, Einon proves even more tyrannical than his father by enslaving the former rebels and forcing them to rebuild a Roman Empire castle. Bowen, believing the dragon's heart twisted Einon, swears vengeance on all dragons.