The story takes place in the bustling metropolis of Paris. A kind lady decides to leave her huge fortune to her pet cat "Duke" (voiced by Eva Gabor) and her children who have been with her all the time. The greedy housekeeper learns of this and begins to think about the inheritance. Late one night, the housekeeper secretly abandons the Duchess and her children in the weedy and uninhabited countryside under the cover of night. In his mind, as long as these cats are gone, his inheritance is as easy as taking something out of his bag. Cold and hunger threaten the lives of the Duchess' family from time to time. Fortunately, a wild cat named Thomas (voiced by Phil Harris) appears in front of the Duchess at a critical moment. With the help of Thomas, the kittens not only grow up healthily, but the Duchess also learns many valuable lessons about how to deal with cats. In the end, they not only return to Paris smoothly and expose the hypocritical mask of the housekeeper, but also a romantic relationship between the Duchess and Thomas.