Ever since Sasami was a little girl, she's admired those who defend justice. She loved watching shows about Magical Girls and Sentai Rangers, but the shows she loved watching the most were police dramas.

Years have passed and Sasami has become a police officer herself. Her first assignment is to go undercover and act as a student at Hanagaki All-Girls High School to make sure there are no corrupt teachers or students there.

One night, while helping out the photgraphy club, they enter the supposedly empty library to find someone there. After trying to run away, one of the club members concludes that she's trying to steal expensive books that should be locked away but are missing. Sasami chases after and catches her, telling her she's with the police. The girl turns out to be her classmate, Sakuraba.

After finding out it was a misunderstanding, she goes to apologize and ask that she keep it a secret that she's with the police. Sakuraba then reveals that she is the police officer in charge of Hanagaki All-Girls High School, and that Sasami must have been assigned there by mistake. Why was Sasami assigned there and what will happen between her and Sakuraba?