Neighbor Saezawa secretly pleasures himself while eavesdropping through the walls on Mei Satsuki and her fiancé's happy apartment life. Clumsy and scatterbrained, Mei accidentally wears her boyfriend's shirt, mistaking it for her own, causing minor daily mishaps. Intrigued by her, Saezawa deliberately sends her packages and then blackmails her into taking responsibility for using them without permission. Feeling unsatisfied with her sex life with her boyfriend, Mei finds herself overwhelmed by pleasure during Saezawa's forceful sex, gradually becoming drawn into a secret affair with him. A thrilling tale unfolds as everyday accidents collide with a neighbor's intense seduction.