Hitomi Shiraki is a carefree, happy housewife in her first year of marriage. Drawn by favorable conditions such as three meals, naps, sex included, and a permanent job with a house included, she even dropped out of the university she had been attending and married Koji, an assistant professor at her school. From the outside, their married life appears happy, but her sex life is full of dissatisfaction. The cause is the presence of her older sister, Yuriko, who is living with them under the condition that she will stay only until marriage. Because she is considerate of Yuriko, her sex with Koji is always incomplete, and Hitomi’s stress is on the verge of exploding.