What happens when individuals discover the world they know is not reality, and that realization places them in a world-changing position? As usual, Haddix uses compelling storytelling to engage readers' minds with significant and fascinating questions, including who to trust and how to strategically discern a means for survival. Young adults, even reluctant readers in the age group, will be enthralled with the sci-fi premise of this novel and the questions it forces readers to consider. Only frustration: waiting for the conclusion, which will be in a forthcoming sequel. From New York Times bestselling author Margaret Peterson Haddix comes the first book in a brand-new thrilling 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.

This news puzzles Nick and Eryn, so the twins set out on a mission to find out who these kids are--and why they're being kept hidden.