Married Woman Travel Moist Disturbed Shellfish (2011)

A woman is found unconscious on a mountain road. She awakens in a room at a local inn with no memory of her identity. Tetta and Rui, the inn's staff, tell her she is Rin Komiya, a guest who is scheduled to stay. That night, drawn by sounds from another room, Rin witnesses the inn manager and his wife. She then instinctively begins to masturbate.