Colton Caine is a rising star in the Houston MMA scene. He’s also had a crush on his stepsister Cassie since her mom married his dad a few years ago. Now that all his brothers are married and settled, they’ve decided it’s time for Colton act on his attraction, and at the annual summer party to celebrate Cassie’s and her mother’s birthday, Colton finally summons the nerve to confess his feelings. Kindergarten teacher Cassie Blackwell has only ever had eyes for Colton. When her mother Gwen married into the Caine family, Colton and all his brothers became her family—and off limits. All the men she’s dated since have paled by comparison. When Colton confesses his longstanding feelings at her annual birthday party, she’s both stunned and thrilled. Cassie’s most recent ex—a fight promoter—shows up at the party and threatens Colton in a very public way, then turns up dead hours later in the family’s house. Days after that, Colton’s manager is murdered, and suddenly Colton’s the main suspect in both murders. As they explore their budding romance, they’re forced to navigate a cranky homicide detective, threats from the dead ex’s business partner, and surviving the final week of the school year, all while trying to solve the murders before becoming the next victims.