Two years into their marriage, their relationship is not bad, but Sumire feels lonely due to her husband's lack of interest. As she worries about how to get him to notice her, her father-in-law Kazuo comes to her for advice... However, no matter how much she tries to persuade him, he remains indifferent, and before he knows it, Kazuo can't take his eyes off her. As he tries to comfort the disappointed Sumire, Kazuo can no longer bear it... From that day on, the two continue their relationship behind her husband's back. Before she knows it, Sumire is seeking her father-in-law's sperm instead of her husband's...