Grandmother Yukie Kurimoto, worried about her grandson who has moved to the city, visits his grandson's boarding house. Though surprised, the grandson is happy to have his grandmother visit and becomes more affectionate than usual. On one night alone, the grandmother and grandson cross the line and lustfully seek each other out, engaging in a creampie incestuous relationship that is a world apart. The grandson's senior from university happens to witness their relationship and threatens Yukie, making her do as he pleases, greedily devouring her ripe body! A young, strong cock dominates her ripe pussy, and Yukie, moaning with pleasure, climaxes and is creampied!