my grandson's body addiction has turned into a kitamori mako.

Asako Kitamori (60 years old) is now single before her husband, and lives with her son and wife in a long land in Sakai Prefecture. His grandson, Takumi (22 years old), lives alone in Tokyo as a university student. Takumi, who decided to take a driver's license by taking advantage of his vacation, returned home after a long time. However, his son and wife (Takumi's parents) went on a trip, and Mako and Takumi were alone. a little cut starts the forbidden relationship between grandchildren and grandma...