Being one of the many fairy races (who live on the border between the underworld and the human world), you become the fiancée of the only grandson of Lady Levi, the 1 of Great 3, named Leviathan Leiji.

The day before the Levialon Academy students' graduation night, you are at a meeting to make a decision about the arranged marriage between you both.

Is it a good idea to be the fiancée and future wife of a tyrant like Leiji? And can you be able to melt his heart?