Mountain Storms — Max Brand

When his father dies in a fall in the mountains, twelve-year-old Tommy is left to fend for himself. Through stamina, ingenuity, and a miraculous alliance with a grizzly cub whose mother he helped, the boy survives. When Tommy is older, he and the bear venture down into the valley where they prevent the killing of an unbreakable horse. The horse, the bear, and Tommy become legend - and an expedition is mounted to capture or kill Tommy.