It's a seemingly happy marriage for Shu and Haruka. Two years into their bond of love, Haruka decides she wants conceive a child with her husband and raise a family. Unfortunately for the two of them, Shu is suddenly unable to perform in the bedroom. According to Shu's doctor, there's nothing physically wrong with him, leaving the problem being something potentially psychological.
In fact, there is something hiding away inside of Shu's mind that's affecting his performance; a fetish that he's only hinted at to Haruka.