Seigi Nakata is a second-year student at Kasaba University who is majoring in economics. He works part-time at a jewelry shop run by the breathtakingly beautiful jeweler Richard. One day, while Seigi is talking to his schoolmate (and crush) Tanimoto, he meets her good friend Shinkai. Through a twist of fate, Seigi finds himself wrapped up with mysterious rumors of a cursed emerald at Shinkai's ballet troupe!