Dia was the daughter of a duke who grew up in the Royal Palace after losing her family.

Upon being told by her fiancé, the First Prince, that their engagement had been annulled, she soon found out—

—that at an approaching ball being held in a few days, she would be killed by none other than her loved ones.

This was a story set at the Royal Palace of a kingdom with everlasting night. A tale concerning Dia, who had lived a sheltered life alone. A story about her trying to painfully persist until the end, despite the heartlessness of her loved ones—

—and also a story about a beautiful, but also merciless King of the Night, who was aware of Dia's predicament. It is a tale weaved around these two people.