It was a Friday. The story begins when Yumi meets Abe, one of her husband's subordinates, who comes to drop off her drunk husband. Both her husband and Yumi are busy with work, and Fridays are the only time they have a chance to have sex...Yumi's desires are growing without her realizing it. Then, a few weeks later, Abe comes to drop off her drunk husband again, and Yumi's sexual frustration is realized. From that day on, the two of them only seek each other's bodies on Fridays...