Jem Coulter’s father (“Pa”), the sheriff of Goldtown, is away on a trip to deliver a prisoner to Sacramento, and he has left Jem in charge of the ranch—along with Aunt Rose, that is.

No sooner is the sheriff gone then trouble starts—a dead calf, a mysterious stranger, and then Pa’s horse, Copper, and his prize rifle are stolen. And Pa’s deputies seem unconcerned.

Jem and his cousin Nathan find Copper’s tracks end at a dark canyon up in the hills. Jem remembers an old Indian legend Strike-it-rich Sam is fond of retelling about people disappearing and no one ever seeing them again. What is the real story of the canyon of danger? Have thieves found the perfect hideout?