Asamura Ryoko, the homeroom teacher of Class 3-1 at Akamine Middle School and a Japanese language teacher, encounters a group of junior high school students robbing money from classmates during her patrol in the bustling nightlife district. She tries to warn them, but ends up being threatened with a knife. Just then, a police officer arrives and apprehends the students for extortion and assault, handing them over to Detective Saegusa Hiroki of the Juvenile Division. The next day, the school is set to introduce a new type of law enforcement officer approved by the Ministry of Education, known as School Police. Amidst the anxiety of teachers like Ryoko, Mizuno Kaede, and Abe Hiroaki, the school principal, Toshifumi Kijima, introduces the man who had arrested the students the previous night, Shimada Ryuhei. Despite being a detective in the Tokyo Metropolitan Police Department's Investigation Division, Shimada volunteered for the School Police. When Ryoko questions his motives, Shimada cryptically states that he wanted to determine if the students of this school were worth protecting. In Class 3-1, Satoru Ichinose is conducting a math class. When Kazuki Sanada is scolded for his behavior during class, he becomes defiant. Shimada arrives and arrests him for property damage and assault. This arrest is soon spread across social media by someone in the class. Shimada instructs Ryoko to identify the culprit behind this incident. Meanwhile, he hears a rumor within the school... (Source: Japanese = thetvdb.com || Translation = MyDramaList)