Adeu the Sonic, brash young pilot of the Ryu Knight Zephyr, is joined in his travels by Princess Paffy, Priest Izumi and Ninja Sarutobi. They encounter various people of the land, including other Ryus. On the way, Adeu seeks to test his Ryu against others and thereby grow in his abilities.

In an old world clash between light and darkness (as always), the evil Lord Uongadis is sealed away under a gigantic monument called the Earth Blade. 20 years have passed since the wars, and now the threat of evil being brought back is greater than ever as demons try to revive their lord.