Three Simple Rules follows Ashley and Sarah, who are both in their late twenties and looking for love. Ashley had set up the rules while in high school, which included no kissing before the third date, always meet in public, and no sex until marriage. Ashley passes these rules on to Sarah after she begins having a hard time finding a lasting relationship. Ashley's goal for the rules was to get back to old-fashioned values. She passes her newfound wisdom on to others in hopes that they, too, will find love instead of just lust.