Six months have passed since her husband passed away, and Yuna has come to stay with her husband's parents. Her brother-in-law is working overseas, so only her sister-in-law, Yuko, lives there. Yuko greets Yuna with a smile. The two beautiful married women live together... And that night, Yuko suddenly kisses Yuna. Although Yuna refuses, the memory of Yuko's lips makes her aroused. Yuko, too, has further desires for Yuna. That's right, when Yuko married into this family, her mother-in-law trained her in the pleasures of lesbianism...