Yui is a wife living with her husband in an old apartment complex. Next door lives Takuro, an elderly man living alone. Having always been fond of grandfathers, Yui takes it upon herself to look after him. One day, while cooking with Takuro, he suddenly embraces her. Saying she resembles his late wife, he spreads Yui's legs and buries his face in her crotch. Despite her desperate resistance, Yui's body responds to Takuro's skillful tongue work. From then on, Takuro greedily craves cunnilingus even when her husband is nearby, and his cock, which shouldn't be able to get hard, begins to stand erect...