Lauren, a pampered uptown cat, becomes stranded in a snowstorm and is rescued by a tabby named Buster, a seasoned street cat. They fall in love, but tragedy tears them apart. Left to fend for herself, Lauren gives birth to three kittens, who are soon forced to survive on their own in Manhattan, after Lauren is captured and whisked away from them. When their sister, Blanche, is taken from them by a kind lady, Sally and Roger make a home for themselves in a secluded west side alley, and invite their new friends, Maxine, Veronica, and Walter, to form a colony, where they all live in harmony.Roaming the streets are the Scratches, a renegade band of antagonistic cats, recognized by their visible "battle scars." Always on the prowl for action, they are joined by a dejected, friendless, Buster.By chance, Blanche is reunited with her siblings. When Sally is caught by Animal Control, Roger enlists the aid of their estranged father, Buster, and his scrappy companions, to help the colony cats rescue Sally and to find their mother, Lauren.