Dear Diary. Today I'm going to kill her. Love, Rose. When Rose discovers the contents of her teenage diary splashed across the pages of a bestselling book, she knows her carefully constructed life is about to unravel. The author, Emily Harper, claims the story is fiction, but Rose knows better. Desperate to find out how Emily discovered her deepest secrets, Rose ingratiates herself into Emily's life, posing as an enthusiastic assistant and adoring fan. But as Rose gets closer to the truth, long-buried memories resurface. Slowly, the horrifying events of her teenage years come into focus, revealing that sometimes, the people you trust the most are the ones you should be most afraid of.