"Who Slept With Her?" takes place in a boys high school, where a bunch of male students and teachers are fascinated by a new student teacher at the school. As is expected, they all fight to get her. But when a rumor spreads that she slept with one of the men from the school, a group tries to find out his identity.

Beautiful, sexy Ji-young is placed at an all boys’ high school as student-teacher. Teenage boys in puberty think of her as a sex goddess and fantasize about her. Then from one of the classrooms, Dean of Students sees a silhouette of a couple embracing and hears a woman moaning. He goes to the classroom only to discover a pair of red stilettos. He suspects Ji-young and is resolved to protect the boys from her sexual charms.