Ted Hammond loves a good mystery, and in the spring of his fifth-grade year, he's working on a big one. How can his school in the little town of Plattsford stay open next year if there are going to be only five students? Out here on the Great Plains in western Nebraska, everyone understands that if you lose the school, you lose the town.

But the mystery that has Ted's full attention at the moment is about that face, the face he sees in the upper window of the Andersons' house as he rides past on his paper route. The Andersons moved away two years ago, and their old farmhouse is empty,...