"Found you." A molester named Tsuji sets his sights on a quiet office lady, Kozue Sato. Taking advantage of the packed morning train where she can't move or call for help, he begins a daily routine of nipple training. After having aphrodisiac oil rubbed into her breasts day after day, Kozue's body becomes hyper-sensitive, eventually being developed to the point of nipple-induced orgasms and involuntary urination.