Yuna, a simple village girl, has her mundane life turned upside down when a mysterious light transports her into the body of a gorgeous saint. In this new role, she faces the disdainful looks of the saint's betrothed, First Holy Knight Asyut, the distant behavior of her companions, and the palace's tense ambiance. Despite her bewildering circumstances, Yuna perseveres in carrying out the saint's responsibilities until a fateful evening reveals dark secrets hidden behind the palace's spiral staircase.