Emi (Haruna Osaka) married her husband Koichi three years ago and was living a happy life. One day, her husband's company suggested that they move into company housing. While her husband was away, Emi accidentally discovered the existence of a secret staircase. It led to the room of Koichi's boss, Tashiro, who lived on the floor above. Tashiro finds her and scolds her. Emi is threatened and raped. Tashiro's sexual demands escalate. Emi is sucked into a whirlpool of carnal desire from which she cannot escape...