Emma Avery has always loved solving puzzles and codes, and now that she's processing a recent autism diagnosis and facing down seventh grade at a new school, they're even more important to her. Then Emma meets Nate Lin. He's popular and funny and ... loves codes, too. He introduces Emma to the Codebreakers, a group of his friends dedicated to cracking codes that have been discovered in the ruins of a nearby ghost town, which are believed to lead to magical objects. But they're not the only ones on the hunt, and when their sinister rivals close in on an object that grants unlimited wishes, the Codebreakers must race to beat them to it before they use it for dark magic.