Sumire works as a secretary to the company president, despite being a married woman. Suffering from a sexless marriage and growing increasingly frustrated, she succumbs to the president's advances and becomes his mistress, serving as his personal outlet for sexual desires. While secretly meeting with the president in his office, they are caught by a male employee. This man has long admired Sumire's beauty and professional demeanor, and upon discovering their affair, he uses the incident to pressure and pursue her.