Sarah, an Upstate New York girls’ hockey team stand-out... Ben, a horse lover from the Pacific Northwest...And Cat, an artistic bird watcher from California. The four have nothing in common except for the head injuries that land them in an elite brain-science center in the Florida Everglades. It’s known as the best in the world, but as days pass, the kids begin to suspect that they are subjects in an experiment that goes far beyond treating concussions….and threatens their very identities. They’ll have to overcome their injuries – and their differences – to escape, or risk losing themselves forever.

    Chess has always been the protector over his younger siblings, Emma loves math, and Finn does what Finn does best—acting silly and being adored. They’ve been a happy family, just the three of them and their mom.But everything changes when reports of three kidnapped children reach the Greystone kids, and they’re shocked by the startling similarities between themselves and these complete strangers. The other kids share their same first and middle names. They’re the same ages. They even have identical birthdays. Who, exactly, are these strangers?Before Chess, Emma, and Finn can question their mom about it, she takes off on a sudden work trip and leaves them in the care of Ms. Morales and her daughter, Natalie. But puzzling clues left behind lead to complex codes, hidden rooms, and a dangerous secret that will turn their world upside down.