Sukeban Deka 3 (Japan)

About

A 16-year-old sukeban (delinquent schoolgirl) named Saki Asamiya is offered by the police to become an undercover detective to escape prison. She initially refuses, so the police blackmail her by offering to pardon her mother, who is on death row for killing her husband, eventually forcing her to accept. Put under the tutelage of officer Kyouichiro Jin, she is given a metal yo-yo that doubles as a weapon as well as a police badge, and is made to infiltrate high schools around Japan to investigate and stop criminal activities. Her first destination is her former school, Takanoha High School, where Saki's place has been taken by the three Mizuchi sisters and their ring of illegal activities.