When Yuuto was a college student, he kindly helped a beautiful woman who got lost in the city. Attracted to his kindness, the woman Houshou Kotoko, fell in love with him at first sight. Guided by her passionate love, they eventually got married.
However, their marriage is also the beginning of the difficult days for the two of them.
As a matter of fact, Kotoko is the only child of the upper class Houshou family which owns many successful businesses, and originally, she is supposed to marry a man from a prestigious family, chosen by her parents. Although Kotoko's strong feelings manage to tie the two of them together, the Houshou family strongly disapproves of their relationship, and only tries to force them to divorce.
Their only hope left, is to have a child. Promised to barely tolerate them if they can leave behind a child, the Houshou family demands them to get conceived.
Kotoko tries hard to get pregnant, but it is discovered that there is a problem with Yuuto's sperm which make it difficult to conceive a child.
In the midst of despair...... Yuuto takes Kotoko for the first time, to his parents' home, the Ikushima family. A family member who has learned of Yuuto's situation── His father Isao, comes up with a certain sinister scheme, offering Kototo, his sperm donation. The worried Kototo, who is grasping at the straws, refuses. But later becomes determined in order to protect her beloved husband.
Thus, the immoral sex in the guise of sperm donation between the ojousama Kototo and her husband's father begins......