Inbi(1987)

Michiko Sakuraba (Mami Ogawa), a secretary at the Morio Kikuchi Law Office, located in a corner of the business district, takes out a concert ticket from her handbag and smiles. After her work is finished, she is going to go with Kikuchi. Then a woman around 20 years old appeared. Kikuchi introduced Michiko to her fiancé, who was surprised. That night, Michiko, deeply saddened, drank a glass alone at the cafe bar. The other guests were couples. Some men and women grope each other's bodies. Michiko returns to her room and comforts herself with a hot shower...

Official site