Suspecting that a treasure hidden by Valentine may be at the root of the Shadow Ranch mystery, Nancy undertakes a challenging search, aided by her friends Bess Marvin and George Fayne. The first vital clue is found in an antique watch and sparks a series of clever deductions and dangerous developments. While seeking further clues, the girls' investigation in a ghost town ends in near disaster when Nancy is trapped inside a building that is toppled by a rockslide -- a rockslide which is deliberately caused. But the pretty titian-haired detective remains undaunted in her determination to solve the m