Thirteen-year-old Tim McCord lives some "two thousand miles back east" with his father Matthew, a veterinarian, and his mother who is very sick. The severity of his mother's illness has resulted in Tim's being sent to spend the summer on the Colorado ranch of his father's Aunt Kate. Soon after his arrival, he visits the high pasture where he sees what he first thinks is a wolf but decides is a German shepherd dog. Aunt Kate believes that it is the "ghost dog" which was left behind by a hiker who was killed in an avalanche around four years ago. In his loneliness, Tim, who has always wanted a dog, strives to make this one his own. He calls it Lobo, later learning that its real name was Hobo. During the summer, Tim makes friends with Danny and Judy, young people about his age who live on a neighboring ranch, and gets to ride with them in a rodeo parade. However, all during this time, he is concerned, even worried, about his mother. She began writing him every week, but all of a sudden she stops. Then Tim himself is seriously hurt while riding in the high pasture when he is thrown by a horse. Has anything happened to his mother? How will Tim's injuries turn out? And will he ever get Lobo to come down out of the high pasture? This book is reminiscent of the golden age of children's literature when plots that contained a lot of excitement or adventure were used as the basis for stories that taught important lessons and illustrated good character traits.