Wilhamina Constance Winston Churchill Ingersol is a little girl who would dearly love to own a cat. But when Wilhamina asks her mommy if she can have one, her mother won't allow it. Owning a pet is a very big responsibility, and Wilhamina will have to get bigger in order to be ready for a cat. But how does one get bigger?
Wilhamina promises she won't pester her parents about the cat, but she is determined to learn how to get bigger. She sets out to gather advice from trusted adults about how to grow into the kind of girl who can take care of a kitty all on her own. As she puts their good advice to use, Wilhamina begins to develop the good behaviors and attitudes of a big girl. She begins to realize that getting bigger isn't just a matter of growing tall. A big girl is also patient, trustworthy, helpful, and responsible.
Will Wilhamina be able to prove to her mommy and daddy that she's ready for such a big responsibility as having a cat?