Emerald is in a therapy session with Dr. Maureen, working on getting to the root of her insecurities. After years of seeing her sisters in toxic relationships, she too has finally received the taste of betrayal. As Emerald talks with her therapist, she begins to open up about her older sisters, Diamond, Ruby, Garnet, Pearl, Sapphire, and Crystal. She describes what she refers to as "love crimes" and the experiences that led up to these heartbreaking moments, changing their views on relationships forever. Along the way, she hammers out twenty-one rules, that serve as a list of dos and don'ts for a healthy relationship. In this novel, a young woman working with her therapist uses her sister's experiences to formulate rules to embrace self-love and have a healthy relationship.