On the back of this book it says:

Miss Minnie is a cat. Or rather, she was a cat. Although she doesn't know why, she is now a human, and she's not at all happy to be one. She still loves to prowl the rooftops at night and gossip with the other cats in the neighborhood. She is mesmerized by goldfish in the aquarium and she still prefers to clean herself with spit.
Like most cats, Minnie knows who she likes. And she likes Mr. Tibbs, a newspaper reporter who is in trouble with his boss because he would rather write nice stories about cats than ask prying questions of people.
As Minnie tries to find and reverse the cause of her transformation from cat into human, she brings Tibbs news from the cats' gossip hotline-the Cats' Press Agency-that becomes the undoing of one of Chillthorn's most prominent citizens, who is not quite the respectable animal lover he appears to be.