A film depicting the underground reality of underwear trading in the backroom of a burusera shop. Four uniformed schoolgirls come to sell their used underwear, subjected to lewd pranks by the shop staff to create stained panties. A shy girl in a simple sailor uniform is brought to climax with a vibrator, leaving thick yellow stains on her panties. A cheerful girl, tempted by higher pay for both underwear sales and personal part-time work, ends up sucking a man's penis. Another girl writhes in distress as a vibrator is applied over her underwear, screaming from the intense stimulation until she reaches euphoric orgasm. A quiet beautiful girl is seduced by a man and submits her body, shown riding him in cowgirl position, convulsing and writhing as she's vigorously thrust into from below.