Every girl needs her best friend. But Hattie Darrow is more like Reid MacGregory’s social oxygen. She couldn’t survive high school without her. Hattie is the impulsive rebel and Reid is the steadfast wing woman. That’s just how it’s supposed to be. But when Hattie drowns off the coast of Maine while vacationing with her family two weeks before the start of senior year, Reid must confront the devastating loss and her own identity crisis, all while hearing and seeing Hattie everywhere. The police declare Hattie’s death a suicide, but it doesn’t make sense to Reid. There’s no way the enigmatic, joyful girl Reid has known for the past five and a half years would take her own life. Reid knows there’s more to the story. And in her grief, she immediately begins to question the circumstances surrounding Hattie’s death—and the secrets kept by the person she thought she knew better than herself. This is the summer that Reid must reexamine everything she knows about alphas and betas, truth and lies, the complexities of mental health, and what it means to step into yourself.