The existence of Earth, a planet of continents surrounded by deep oceans, has long become a mere legend. People live now on islands which are floating high in the skies. They also have wings - "Wings of the Hearts" - growing on their backs. Kalas is a young man who was born only with one wing - he replaces the second with an artificial wing manufactured by great masters. He is on a quest to find the murderers of his grandfather and his brother. He meets a girl named Xelha, who is out to stop an evil conspiracy that threatens the country, and they join forces against the newly appeared evil.