To safeguard his life from potential assassins, the head of the Hitotsubashi crime syndicate, Gen Shiomi, has no choice but to go into hiding. Despite opting for plastic surgery, the 56-year-old emerges looking like a teenage girl. Nonetheless, he decides to maintain his new appearance until he can be assured of his safety. However, he finds it challenging not to behave suspiciously. Fortunately, Tatsuya Umemiya, a teenage boy, saves him from being apprehended by the police. In return, Gen assists Tatsuya out of his own predicaments. To keep his cover, Gen must attend junior high school under the alias "Shiomi Iwao." Unfortunately, he discovers Tatsuya is one of his classmates.
