Grieving her infant son, Riley discovers her husband Ethan cheating with her stepsister, his true mate. Ethan's cruelty prompts Riley to declare an open marriage. She then drunkenly signs a contract binding her to three powerful Alpha brothers, Ethan's friends. They reveal their influence and Ethan's plot to erase her from their company. Riley confronts Ethan, who confesses to poisoning their son to have an heir with his true mate. The Alphas brutally beat Ethan, terrifying Riley. Sebastian, the Alphas' father, proposes the deadly "Rite of the Borrowed Moon" for Riley. Despite her fear, Riley accepts the Rite, but is now trapped and deeply afraid of the Alphas' violent nature.
