A case of mistaken identity reveals a twin's horrifying secret in this twisted tale from the bestselling author of What Janie Found.

Mary Lee and Madrigal are identical twin sisters, inseparable since birth-until the day their parents inexplicably send Mary Lee away to boarding school. While Madrigal flourishes at home, growing popular and even landing a boyfriend, Mary Lee spends her days at school feeling lost, lonely, and envious of her sister's perfect life.

Then Madrigal comes to visit Mary Lee, and what should have been a fun weekend ends in tragedy. When everyone mistakes Mary Lee for Madrigal, the second-best twin steps into the life of the favorite. But while everything about Madrigal was perfect from the outside, what Mary Lee discovers about her twin is both shocking-and pure evil.

Caroline B. Cooney has thrilled millions of readers with her Janie series. Now she explores the sinister side of secrets in this shocking novel about two very different sisters.