Set in present day Tokyo, Shishio Homare works as a freelancer crime consultant. From an early age, Shishio Homare has been fascinated with how people become criminals and in original sin. He is a genius, but he also has an impulse to commit crimes. Shishio Homare works on cases which interests him among police or customer requests.

Meanwhile, Junichi Wakamiya is a psychiatrist. He is smart and cool-headed. Due to a case, Junichi Wakamiya gets involved with Shishio Homare. At first, Junichi Wakamiya thinks Shishio Homare is ignorant and arrogant, but, as they work together, Junichi Wakamiya gets comfortable with Shishio Homare.