Hinako was hired by Principal Kuno on her reputation as an 'enforcer' and bringing juvenile deliquents justified 'discipline' and keep the student body in line. He and the school were very surprised when what appears to be a cute ten year-old girl shows up. Her expertise as an enforcer of discipline become apparent when she interupts Happosai's daily panty raid on the girl's locker room and she shouts "Happo ten yen Satsu" and absorbs his battle aura through a ten-yen coin (it has a hole in the middle) and is transformed from a little girl in to an extraodinarily well-built woman. Happosai is rendered completly weak and defenseless as if all his strength had be drained from him.

Ranma naturally wants to learn this new technique and in an effort to get her to like him he ends up taking the little girl to the fair and spending a lot of money on her, but she refuses to tell him. Happosai tells Ranma that this terrible technique was his invention. He relates the story of how 15 years ago he was raiding a nurse's dressing room at a hospital and saw a very sickly and weak little girl. In order to help her he taught her basic exercises, pressure points and how to absorb other's battle aura to make her stronger. She grew stronger and Happosai got her help with his raids. He tells Ranma that he must neutralize her power or it will mean the end of Anything Goes School of Martial Arts. This can be done by pressing several pressure points at the exact same moment. Two on the back and three on the chest.

Ranma tries again and again the hit the pressure points. He fails and has his battle aura drained. There is the additional result that now everyone thinks he's a total pervert because he is constrantly trying the grope her chest. After a full scale combat he manages to trap her arms and deliver the pressure points, rendering her unable to absorb his battle aura. Thinking its all over, Ranma is agast when Happosai tells him he now has to do it 23 more days in a row for the disablement to be permenant. Ranma gives up.