Jun engages in a secret, passionate affair with his teacher, Ms. Keiko, who is also the mother of his classmate, Sae. When the guilt of their relationship drives Keiko to abandon her family, Jun reveals the truth to a devastated Sae. Feeling betrayed by both her mother and her peer, Sae demands a twisted form of restitution, forcing Jun to submit to her as a replacement for the family he helped destroy.
Jun navigates a precarious double life, indulging in a passionate affair with Sae while her mother, Keiko, is away. Despite the thrill of their secret encounters at school and a clandestine reunion with Keiko, Jun is consumed by guilt over the betrayal. The tension peaks when Sae unexpectedly suggests that they go to the police together.