Seong-hyeon, a college student, starts working as a private tutor for Ji-woo, a high school senior who is struggling with his grades. When Seong-hyeon visits the house, he meets Ji-woo's glamorous and lonely mother, Seo-young. While Ji-woo is uninterested in studying and sneaks out to meet his girlfriend, a dangerous attraction begins to grow between the young tutor and the lonely mother under the same roof.