Sex Girl 10: In a big house that suddenly opened, a boarding student is looking for someone to share money and loneliness with. A boarding student happened to come to Ga-yeong's house through a friend's introduction. However, the boarding school student, who naturally thought she was a woman, was an adult male, and Ga-yeong continues to be wary of Hyeon-min. However, as soon as she finds out that Hyeon-min is a good person, Ga-yeong seduces him. Meanwhile, Hyeon-min's friend Jeong-woo happens to visit Ga-yeong's house... and the sweet and bloody story unfolds between two friends with a woman between them.