The Alley Cats introduce Berlioz, Marie, Toulouse and their mother Duchess - the richest cats in all of Paris. When the Aristocats' beloved owner Madame announces that she has left them all of her money, Edgar, the family butler, becomes very jealous. While the Aristocats practice singing Edgar warms some milk. After they fall asleep, Edgar takes the Aristocats out into the country and leaves them in a ditch.
As the Aristocats wake up, lost and alone, Napoleon and his pack of Country Dogs chase Edgar away. An Alley Cat named O'Malley discovers the Aristocats (Thomas O'Malley Cat), who are surprised to find him friendly. Despite the protests of the other Alley Cats, O'Malley agrees to help the Aristocats find their way home to Madame. Napoleon and the Dogs find the Cats and chase them. When Marie falls into a river, O'Malley dives in to save her, only to be saved himself by a pair of Geese, Abigail and Amelia (The Gabble Girls). The whole gang waddles back to the city.
In Paris, O'Malley and the Alley Cats show the Aristocats the benefits of their freewheeling life. Duchess invites O'Malley to come home with her, but he decides to stay in the alley. Surprised to find them home, Edgar traps the Aristocats and prepares to ship them to Timbuktu. Roquefort the Mouse runs off to get help from O'Malley. The Dogs and Geese join the Alley Cats to save the Aristocats and ship Edgar away. Madame celebrates the return of her precious Aristocats and agrees to take in all their friends as her treasured pets.