Saki, a married office worker, commutes to work by train five days a week, from Monday to Friday. One day, a habitual molester targets her voluptuous breasts and plays with them greedily. The molester's obsession with her big breasts escalates day by day. He becomes excited by her arousal, even though she resists, and continues to molest her, teasing her nipples with toys and massaging her breasts with aphrodisiac oil. After being toyed with repeatedly, the married woman's body is transformed into a breast-climaxing slut with no turning back...