Kenji lends Tomoko, a female college student who lives in the same apartment building, a shoulder to lean on when she is stuck on the stairs. A few days later, Kenji bumps into Tomoko on the way home from drinking with a colleague from work and they end up drinking together at Kenji's house. Tomoko seduces him, and Kenji can't resist and ends up having sex with her next to his drunk colleague who is sleeping. Kenji's younger brother, who is watching, approaches him, wanting to taste her huge breasts too...