Yoshie has long been targeted by Nojima, her son Taichi's friend who is around her own age. One day, while Taichi is away, Nojima shows up and ties her up with rope, raping her helplessly. Lewd photos are taken during the assault, and from that day forward, Yoshie is forced to obey Nojima's every command. Later, she is repeatedly tormented in front of Taichi by Nojima and his gang, as Nojima's obsession grows without end, driving him to seek even greater humiliation. Eventually, he plans an overnight study session filled with shame, turning it into a grand event centered around Yoshie's voluptuous mature body.