it's been 5 years since i left my parents' house and lived in tokyo. i came back to my parents' house for the first time in a long time. my parents and grandfather live in my parents' house. my grandmother passed away, and my mother is taking care of my grandfather, who is depressed and half bedridden. my father is not interested in the family and is always out. one day, a strange voice leaked from my grandfather's room. it sounded like a very exaggerated animal sound. i was curious, so i quietly opened the shoji screen. then... in the room, there was a vulgar figure of my mother moaning while her breasts were being devoured by my grandfather, and my grandfather was also lovingly playing with his dick...