Emi (Haruna Osaka) married her husband Koichi three years ago and has been living a happy life. - One day, at the suggestion of her husband's company, she decided to move to company housing. - While her husband is away, Emi accidentally learns of the existence of a secret staircase. - It led to the room of Koichi's boss, Tashiro, who lived on the upper floor. - Tashiro finds out and blames him. - Emi is threatened and raped. - Tashiro's sexual demands escalate. - Emi is swallowed up by a whirlpool of lust that she cannot escape...