Life is good when you’re a carefree young squirrel from a respected working class family living in the west side of New York City’s Central Park. At least HJ “Hoppin’ Jack” Graytail thinks so. There’s plenty of mischief, excitement, and fun to keep him and his best pal, a chipmunk named Chipper Quicktoes, very happy. Of course there’s school, too, but as long as you can keep out of the way of the Raccoon Brothers, who are the class bullies, that’s not too bad.
Life gets all the more interesting when HJ and Chipper happen to meet a lovely red squirrel named Lucky Rutherford and her next-tree neighbor, a clever black squirrel named Jet Burrelston. In spite of the fact that Lucky and Jet hail from well-to-do families on the Upper East Side of the Park, it doesn’t take long for the four to discover you shouldn’t judge a squirrel by its neighborhood and they become fast friends.
Just when HJ and Lucky are finding how much they like each other’s company, the Park’s community of woodfolk is terrorized by a series of murders. A tough gang of alley cats from a nearby neighborhood is moving into the Park and has decided to take over. Led by a merciless tom named Snake, these thugs have nothing in their hearts but a craving for power and violence. They mean business—bad business.
When the aging police force of the community, called the Protectors, is overrun by the cat gang, HJ and his friends suddenly find themselves in the forefront of a battle to save the animals of Central Park.