Jin, a detective, persuades Saki Asamiya to become part of a team of youth detectives, who work undercover. He proposes that if Saki agrees to enroll after serving time in a correctional facility, he will act on behalf of her mother who is facing the death sentence. Saki endures challenging training and adopts a disguised identity to investigate cases of illegal conduct, wrongdoing, and extremist behavior at different high schools as if she were a student.