A young boy and a girl with a magic crystal must race against pirates and foreign agents in a search for a legendary floating castle.
In the ancient time, the human honored the winged clan as gods for their ability to fly and to build a castle in the sky. The day when the castle was to be lifted off the ground an explosion destroyed it. A human girl was suspected to have the done deed. However, a man from the winged clan didn't believe it and saved her life. As it turned out, it was a faction of the winged clan trying to start a war with the humans in order to expand their control.
Adol Christin, a young man from the mainland, sails to the besieged land of Esteria in search of adventure. Esteria is being overrun by beasts under the control of the evil priest Dark Fact, and the people of the land are running out of time. However, there is a prophecy that tells of a hero from another land who will come to save Esteria -- and his name would be Adol Christen.