His mother's hospitalization results in thirteen year old Tim McCloud's summer on his great-aunt Kate's ranch. In her high pasture he tries to attract a German shepherd believed to have run wild since an avalanche caused the death of a former master. Death's inevitability seems to be the book's main theme, as the death of an old collie early in the summer foreshadows later news that Tim's mother has died. A grief-stricken Tim falls from a wild bareback ride to the high pasture. He is roused from unconsciousness by the German shepherd washing his face. Lobo goes for help and becomes Tim's dog. The story ends with the prospect of Tim's full recovery from his injuries and the decision of his father to move to the ranch where he will continue his practice of veterinary medicine and permit Tim to keep the dog. Rough black and white illustrations do not relieve the story which suffers from trite expression, typical western topography and characters, and a somewhat too pat acceptance of death by all concerned.