The neighbor of the apartment where Mei lives happily with her engaged boyfriend is a pervert who masturbates while eavesdropping on Mei's conversations through the wall. - Mei is a bit of a clumsy girl who accidentally wears her boyfriend's shirt thinking it's her own. - Saeyama, a neighbor who notices this, deliberately sends a package and threatens Mei, who used it without permission, to take responsibility. - Mei, who was feeling unsatisfied with her night with her boyfriend, feels pleasure from Saeyama's f** sex...