After losing her husband, Aoi, a single mother who has been raising her only son, Takahiro, is unable to earn enough money and has to offer her body to her boss, Onuki, to make ends meet. However, the perverted Onuki is not satisfied with just having sex with Aoi and begins to become interested in her anus. In order to survive, Aoi continues to have her anus played with almost every day as she is told... Finally, her anal virginity is taken, and she unexpectedly reaches orgasm. Seeing this, Onuki, wanting more excitement, comes up with a plan...