I work in Tokyo and return home for the first time in ages, where my parents and grandfather live. Since my grandmother died, my grandfather has been depressed and nearly bedridden, so my mother cares for him while my indifferent, alcoholic father ignores the family. One night, strange, heated moans come from Grandfather's room. I quietly slide open the door and discover my mother happily stroking his cock while he sucks her breasts—a sight that changes my desires forever.