After confessing his love to the seemingly docile Sakurai Erika, Sayama is shocked to discover her true identity as a nymphomaniac who craves sexual encounters with numerous men. Instead of a traditional relationship, Sakurai proposes a perverted arrangement where Sayama serves as her personal cameraman. Bound by their shared hidden desires, Sayama begins documenting Erika's increasingly extreme sexual exploits, from secret trysts with her landlord to daring public encounters.
Erika continues her habit of sleeping with strangers while Sayama films her encounters. After a distressing experience with an older man, she finally gives in to her feelings for Sayama, sharing a passionate night of love and intimacy. However, the moment is short-lived, as Erika abruptly drops out of school and disappears, leaving Sayama with a letter explaining her drive to experience more men.