I am a little terrier who belongs to a boy named Don...
Don; Teddy (dog); Mr. Nelson
Don goes to summon a doctor for his grandfather during a snowstorm, but is hurt during the trip. Don's dog, Teddy, instead makes the trip to the village and manages to summon the doctor to treat Don and Don's grandfather, Mr. Nelson.
The story is from the point of view of a dog named Teddy.