Synopsis：Shiori Sato was sent to the worst class, Class F, at Seika High School for 100,000 yuan by her mother. On her first day, she is extorted for protection money by the gang leader, Sho Kano, but collapses penniless and is taken to the hospital by Kano. The two make a deal: Sato will write her homework for her and Kano will provide her with three meals a day. Sato comes in first in the entire school on the monthly test, but everyone in Class F is at the bottom. Sato is insulted by the head teacher, and Kano, angered, makes a bet with the teacher, vowing to raise Class F's average score by 20 points. Sato teaches Class F using her fun "delinquent slang explanation method," and together they achieve a score that exceeds the target, winning the bet. Afterwards, Sato is blackmailed by her stepfather and has a hitman hired by her mother, and is hit one after another, but Kano repeatedly protects her at great personal risk, and in the process, it is revealed that he is the heir to the Kano family. Kano is nearly expelled for fighting to save Sato, but Sato works with Class F to gather evidence, Kano's father appears and reveals the truth, proving Kano's innocence. In the end, all of Class F pass their university entrance exams, and at the graduation ceremony, Kano passionately confesses his feelings to Sato, and the two become a couple.