The Roland Kingdom, once known as the Kingdom of Patriots, is now divided between the Royal Faction, which backs the Second Prince (son of the Queen Consort), and the Church Faction, which backs the First Prince (son of the Concubine), leading to political turmoil. Due to this disarray, Lady Julianna, daughter of Marquis Lewis, who possesses a unique bloodline and is known as the "perfect lady," was the focus of high society's attention regarding who she would be engaged to.

One day, with less than six months until Julianna's engagement announcement, a summons arrives for Julianna from the Second Prince. Then, the Second Prince, who is supposedly revered as the "ideal prince," delivers a fiendish declaration to Julianna that she is merely his pawn. In order to fulfill her own desire and unwillingly uphold her promise to the Second Prince, Julianna infiltrates the Royal Capital Church, where devil worship is being practiced, and becomes embroiled in the conspiracies of both the Church Faction and the Royal Faction.

――I swear on my pride that I will deceive everyone and play my part to perfection on this life-or-death stage.