Isobel lives in a ramshackle country house in England with her father and her cat, Augustus. Her father is an inventor and Augustus, alone among his kind, has the power of speech - which is rather a mixed blessing as he seldom has anything nice to say about anyone. The fun begins when Isobel asks her father to invent her a flying broomstick. The inventor demurs because he is too busy perfecting his All White-Meat Chicken, instead he offers her one of his previous creations - Avery Small-Elephant. Avery, it turns out, is indeed a very small elephant - about the size of a Labrador retriever. Isobel is rather disappointed about the broomstick but she soon warms to her new friend, as does Augustus after some initial kerfuffling. So far, so good. But then disaster strikes. Isobel's father and the All White-Meat Chicken are kidnapped by gangsters posing as tycoons. The gangsters believe the chicken will revolutionize the eating habits of all humanity and make them rich men into the bargain. When the authorities prove to be of little use, Isobel and her friends turn detective and set off for the city to rescue both chicken and inventor.