Ayumi is a married woman in an ordinary, loving marriage. Facing financial struggles, she finds herself unable to cover their mortgage with her husband's salary alone, so she begins working as an esthetician at a men's spa. Inside the shop, excessive services become routine, and under the guise of a "special course," Ayumi repeatedly engages in unprotected sex, gradually awakening her own suppressed desires. One day, her client turns out to be her husband's boss at work. This encounter triggers a dramatic shift in their marital relationship.