Rui Kamishiro is a professional detective who works with his assistant Tsukasa Tenma. Rui is very responsible about his work and wants to do everything to protect his city. He doesn't like police officers because he thinks they don't do anything. But he is forced to cooperate with them and they provided him and Tsukasa with an office. Since he is good at solving cases, many people hunt him in the city and often harm him when he is alone. He may look harsh.