When work takes Cassie's mom abroad, Cassie is stuck living with her dad in his Winnebago in Palo Duro Canyon State Park for the summer. She loves her dad, but he's different since the divorce, and for that matter, so is she. She's gotten used to a different lifestyle that's not exactly compatible with the rougher living in the Canyon, where her dad is a handyman. She misses the conveniences of city living, and she's not too sure about the kids here. They seem awkward. Uncool. And, in the case of mysterious X, possibly dangerous. When several arrowheads go missing from an archeological dig site on park property, Cassie immediately has a suspect in mind. But when she starts jotting down clues in a detective journal and putting the pieces together, Cassie feels uneasy. Have her assumptions about other people led her down the wrong path?