Keiko Kubota is asked to stay over for a week to help her father-in-law Masahiro prepare for his new bar opening. However, Masahiro, whose strong libido hasn't diminished with age, has long desired Keiko's body and skillfully takes advantage of her vulnerable state after she gets drunk that night. The next morning, Keiko regrets the irreversible mistake she's made, but finds herself powerless as Masahiro now holds a compromising secret over her. From then on, she is plunged into a life of unbearable humiliation, unable to seek help from anyone, and is gradually driven to the edge.