Romance novelist Sienna is secretly a sex addict. When a minor mishap forces her to seek treatment, she is shocked to find her therapist is Casten—the college football star ex-boyfriend she dumped five years ago over a heartbreaking betrayal. Issuing a strict one-month abstinence order, Casten steps back into her life, transitioning from a cold, professional doctor by day to a fiercely possessive predator by night. As buried secrets, family moral debts, and intense physical desires collide, Sienna must face a dangerous reality: she is completely addicted to the one man she swore to hate forever.