Debra discovers that her mother-in-law, Marie, likes Robert's girlfriend, Amy, better than she likes her because Amy is a "good girl." When Robert accidentally lets it slip to Marie that Amy is a virgin, Marie is thrilled to pieces. Jealous of the attention Amy is receiving from Marie, Raymond minimizes Debra's premarital activities, leading his mother to believe that Debra was a "good girl" too. When the family discovers why Marie has this sudden "purity" fixation, Robert and Raymond are in for a big surprise.