Sukeban Deka

is a Japanese shōjo manga series written and illustrated by Shinji Wada and serialized on Hana to Yume magazine. It has been adapted into three live-action television series, an OVA series and three feature films, the latest of which was released in 2006 as Yo-Yo Girl Cop.

Plot
A 16-year-old 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 doubled as a weapon as well as a police badge and made to infiltrate high schools around Japan to investigate and stop criminal activities. Her first destination is her very former school, Takanoha High School, where Saki's place has been taken by the three Mizuchi sisters and their ring of illegal activities.

Other Wikis

 * Sukeban Deka at J-Drama Wiki