Rie, who lost her husband in a traffic accident three years ago, lives with her step-son, Yuma. Yuma is attracted to his young and sexy stepmother. Meanwhile, Rie has been living a frustrated life, having kept her chastity for the past three years. One day, Saki, the wife of Yuma's older brother, Haruma, who died in the same accident, comes to visit, and their relationship takes an unexpected turn...