After attending their sister's wedding, three high school girls, Seong-eun (Kang Eun-bi), Soo-yeon (Jeon Hye-bin) and Mi-sook, have a lot of fantasies and look forward to their prince charming coming soon... Kang Bong-gu (Lee Ji-hoon), a handsome physical education teacher who has just graduated, is troubled by his strange body that farts when facing women's excitement. However, this does not prevent him from becoming a popular lover of girls during his internship at a girls' school. Seong-eun and the domineering campus model Baek Se-mi (Shin Joo-ah) are both interested in Kang Bong-gu, and a competition is inevitable. Seong-eun, who has a flat chest and no experience in interacting with the opposite sex, is at a disadvantage everywhere. The two sisters Soo-yeon and Mi-sook helped plan a series of actions to win over boys, such as studying boys' excitement points, peeping into men's locker rooms, and anonymous tape confessions, but they never worked. Faced with Baek Se-mi's step-by-step pressure, Seong-eun decided to go all out and broke into Kang Bong-gu's home at night...