I remember Kjelgaard for his books about Irish Setters (Big Red, etc) and teenage boys learning be men.
This 1957 book is about a cat named Frosty, a young man who lives in a swamp, a bunch of wild critters, hillmen, townsmen, and muskrats.
Sounds weird, but it works. Frosty is just a kitten when we meet him, and he is about to be taken out to the swamp and left there. That is because the despicable Luke from the hills has a money making scheme: he gets paid to take unwanted puppies and kittens away from the people who live in town. No one ever stops to think what he might be doing with all those little pets, and the truth is he just leaves them to their fate. What does he care, once he has the money?!
But what he doesn't know is that Frosty is not your every day run of the mill cat. No, Frosty's mama may have been a pampered house kitty, but his daddy was the biggest, meanest wildest tom cat around. And Frosty was the perfect blend of the two. He was bigger and smarter and tougher than his two siblings. So he survived after Luke dumped them. And while Frosty learns about the thrills that come with living in a swamp, we get to have a peek into that unusual environment too.
When Andy meets Frosty (dramatic first encounters are always memorable!) a new and surprisingly loving partnership is born. Andy has a dream to turn his swampland into a muskrat farm. He buys and releases dozens of pairs of muskrat, then proceeds to protect them as best he can from the predators in the swamp, including that horrid Luke. Will he have to revive an old hill-family feud to keep that man away from his property?
How does Frosty help out? He always seems to be the cat on the spot, especially when Mr. Luke is around. Frosty has never forgotten him. And Frosty wants his revenge. Does he get it? Will the muskrats survive and thrive the way they do on paper when Andy dreams of the future?
Another unique Kjelgaard look at a part of the natural world that is probably long gone by now.