From New York Times bestselling author Margaret Peterson Haddix comes the first book in a "crisp, intriguing, and thought-provoking" (Booklist, starred review) new series about twins who are on a quest to discover the secrets being kept by their new family.

Nick and Eryn's mom is getting remarried, and the twelve-year-old twins are skeptical when she tells them their lives won't change much. Well, yes, they will have to move. And they will have a new stepfather, stepbrother, and stepsister. But Mom tells them not to worry. They won't ever have to meet their stepsiblings....