The story is set in the medieval European world. The daughter of a marquis who loves reading, Iriana, and the crown prince, Christophe, have a nominal engagement for their own needs. One day, Iriana misunderstands that the prince has found the girl he truly loves, and is ready to cancel the engagement, which leads to various events and involvement in the conspiracy of the royal family. The original novel was originally serialized on the novel submission website "Become a Novelist", and was later published by Ichijinsha. It was also adapted into a comic version.