In the past, humans treated the winged clan as gods because they could fly and build a castle in the sky. On the day that the castle was to be lifted off the ground, an explosion destroyed it. A human girl was thought to have done the deed. But a man from the winged clan didn't believe it and saved her life. As it turned out, it was a part of the winged clan trying to start a war with the humans so that they could get more power.