Meet Margaret. At age twelve, she was head detective of the mystery club Girls Can Solve Anything. Margaret and her three best friends led exciting lives solving crimes, having adventures, and laughing a lot. But now that she's entered high school, the club has disbanded, and Margaret is unmoored—she doesn't want to grow up, and she wishes her friends wouldn't either. Instead, she opts out, developing an eating disorder that quickly takes over her life. When she lands in a treatment center, Margaret finds her path to recovery twisting sideways as she pursues a string of new mysteries involving a ghost, a hidden passage, disturbing desires, and her own vexed relationship with herself.