Natsume Kiroemon is the 45th leader of the Natsume family to inherit the Kouryuu no Mimi, a tool which gives its bearer easy access to wealth and women. As a result of his father’s death, he leaves the Italian monastery where he had been training and to rightfully take on the name Natsume Kiroemon as well as the power of the Kouryuu no Mimi. Upon his return to Japan, he falls in love with Kanako, one of the members of the rival Mina family. However, the evil hand of the Mina family attacks Natsume repeatedly and abducts Kanako. But now that Natsume has unlocked the seal, making the Kouryuu’s power surge, he can strike back at the Mina family.