His older brother and his wife went on a trip overseas, and Takashi returned home from Tokyo to look after them. A week later, when they returned from overseas, Takashi was surprised to see his brother's wife, Yuko, who was a beautiful fair-skinned woman, tanned to the point that her swimsuit marks remained. Although he knew he shouldn't look, Takashi followed Yuko's tan lines with his eyes, and Yuko smiled and asked, "Want to see the tan lines under my clothes too?" Desperately trying to suppress his desire, Takashi decided to return to Tokyo, but his brother had to go on a sudden business trip, leaving him alone with his brother's wife...