A cyclical curse threatens the Disodart Continent as the emergence of the "Black Devil" approaches once more, an ancient calamity that only the priests of Gardis's Central Church possess the sacred knowledge to contain. When the entire garrison protecting the sealing tower mysteriously falls, suspicion grows that someone within the kingdom actively works to accelerate the devil's return rather than prevent it. Desperate to uncover the truth behind this catastrophe, the royal capital assigns a church priestess to investigate the tower—only to discover she is an inexperienced young woman thrust into a conspiracy far larger and more dangerous than anyone anticipated.