Shadow is a wise, old golden retriever. He is very loyal and obedient toward his owner named Peter Seaver, a teenage boy who loves him very dearly. Given his age, he sees the way of a dog as his own law. His pet comrades are Chance, a young, immature American bulldog and Sassy, a Himalayan cat who respects Shadow despite him being a dog. He considers himself Chance's guardian as he feels he must watch over the "pup" and keep him from out of trouble. Chance thinks of him as an old fusspot and calls him "old timer," but still has respect for him as well. For an old dog, he can hold up on his own, as he is able to outrun a mountain lion and keep up in a fight against mean stray dogs.
