Twelve-year-old Corabelle Quinn is positive she doesn't have a single living relative, much less a quirky great uncle named Professor McNitt. But after ten months of sharing a bedroom with a biting toddler and a money-obsessed boy genius named Aiken, she gladly moves in with him anyway. As it turns out, Professor McNitt is not only an inventor of bizarre and marvelous things, but the only person who knows two very important secrets: the real story of Cora's family, and the hidden passage to Gambit Island. But just when he begins to reveal how these two things are closely intertwined-he suddenly vanishes. If Cora wants to save her uncle, she will have to forge through the unexplored, unpredictable land of Gambit. Her only aids? A little black book of codes and symbols, and smug, know-it-all Aiken. In Gambit, Cora and Aiken certainly do not expect to find a technologically advanced city of sprykes (fairies who are not allowed to use their wings), a coalition of civilized animals, a tribe of mermaid descendants in a golden city, or a clan of lost Vikings. But at least they are friendly. Have you ever been chased by hornet-riding cavemen? By the half-dead in a cavernous labyrinth? By shark-human hybrids? Consider yourself lucky. But even they aren't as terrifying as the person holding Professor McNitt hostage. As Cora and Aiken race across Gambit Island, they slowly piece together the mysteries of its origin-and how closely they are each tied to it.