Isobel makes friends with Butch, a sad, skinny stray dog, when she's cycling to and from school. She takes him home to her ma and pa, who say he must go to the dogs' home. But when Butch saves Isobel from a horrible man who wants to steal her bike, her parents relent and say that Butch can stay, as long as Isobel promises to look after him.
Isobel and Butch are soon inseparable, but Ma is not very happy with Butch. He's messy and he eats too much. Then, when poor Ma has an accident, Butch proves his worth and is forgiven for his muddy paws.
Butch and Isobel are a great team Whether finding a lost little boy or helping Hamish, the village policeman, to catch burglars at a party, Butch's helpful personality (not to mention his enormous appetite ) make him a very special dog.