Prince Gerard Himerce seeks vengeance against the Zar Harc Empire for the destruction of his homeland, the Kingdom of Avalon. Joined by the half-human fairy Elaine Shee, last survivor of her clan, and Galahad, an exiled duke from the land of the dragons, the Prince goes on a journey to prevent King Darkness (formerly known as Albert Himerce, Gerard's older brother), the leader of Zar Harc, from reviving an ancient demon. Along the way, they are guided by a mysterious spirit known as the Warrior of Flame, who tells them to seek three keys that have been scattered around the world in order to enter the floating citadel of Gaiapolis.