Photographer Nellie Burns and her faithful Labrador retriever, Moonshine, travel to the Stanley Basin of central Idaho with sheep rancher, Gwynn Campbell, and his Basque sheepherder, Alphonso. Nellie plans to spend several weeks in the mountains around the basin at a sheep camp, photographing scenes for a railroad company's travel brochures. When their group arrives at the camp, however, they discover the current shepherd is dead.

Basque sheriff Asteguigoiri arrives to seek the murderer and reluctantly accepts Nellie's help in the investigation. But when hapless tourists, lawless moonshiners, and hell-bent cowboys enter the picture, Nellie and Moonshine confront some of the greatest challenges yet to their courage and ingenuity.