A female college student, Yume, is excited about tomorrow's trip with her boyfriend, Takumi, when she is unfortunately run over by a truck and dies. - However, when she wakes up, a mysterious man named Kei, who calls himself "Inma," is right in front of her. Yume is confused when she is told, ``You have been reincarnated as a demon succubus,'' but she has no choice but to accept her strange appearance and the tail she has grown on herself. Even though she hasn't even had her first experience with her beloved boyfriend yet, Kei slips his fingers into her body, saying it's just new employee training. Her body becomes sweet and wet due to her lustful nature, and she writhes in pleasure, but her love for him is not easily accepted... What will happen to the girl's heart, which is complicatedly wavering between her ``life as a demon'' and her ``feelings for him''? A sweet and painful triangle love where the feelings of Kei, Yume, and Takumi are intertwined!