Mako Oda, a 36-year-old big-titted married woman, lives in an apartment building. The building manager becomes obsessed with her large breasts. Burdened by gambling debts, he kidnaps Mako to hand her over to a loan shark and settle his debts. The loan shark immediately organizes a large-breast humiliation event, gathering salarymen who love bukkake and charging them for participation. They collectively assault Mako against her will, using her as a target for group facials. She is then turned into a sex slave and subjected to intense training and complete domination.