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.