Tsukasa, in modern times, despite his fame and handsome face, had a shockingly dry love-life; having never even kissed a girl throughout his 18 years. All of this changes during the New Stone Age, when he falls in love, for the first time, with a one-of-a-kind young woman. Liv. She is his ideal woman in every aspect. And she naturally bonds with and cares for his little sister, Mirai: later saving her life from an assassination attempt. Yandere Tsukasa, gentle, protective, possessive, obsessive.