50 years ago, Black Dragon appeared in the once peaceful land of Lagendia. Under the order of the King, the young Geraint, Argenta, Velskud and other legendary heroes assembled various forces to form the Dragon Slaying Alliance. This incident was widely referred as the First Dragon Invasion by the generations to come. However, what exactly happened during this incident? Where are these heroes after the dragon invasion? The movie will reveal the story and mysteries behind this epic historical event.