
In 1910, the Duchess's mother cat and her three children (Berlioz, Marie, and Toulouse) lived in Paris with retired opera diva Madame Adelaide Bonfamille, and her British butler, Edgar.
Cats are spoiled pets that lead a lavish lifestyle, and are as cultured in art and music as their owners.
One day, while preparing her will with the old lawyer Georges Hautecourt, the Madam stated that her great fortune would be handed down first to her cats, then returned to Edgar after they all died.
Edgar overhears this through a talking tube and, after mistakenly calculating that he will die before he can inherit, plans to eliminate the cats.
He drugged them by putting sleeping pills in a plate of cream, then riding his motorcycle out into the countryside in a basket.
There, he is ambushed by two dogs named Napoleon and Lafayette, losing his hat, sidecar, umbrella, shoes, and basket before escaping.
The cats are left stranded in the countryside, while Madame Adelaide, the Roquefort rat, and Frou-Frou the horse find out of their absence.
In the morning, the Duchess meets an alley cat named Thomas O'Malley, who offers to guide her and her kittens to Paris.
The group hitchhiked in a milk truck before being driven out by the driver. Then, while crossing the railway bridge, the cats dodged the oncoming train, and Marie fell into the river.
O'Malley immediately dived in and rescued her, and she herself was saved by Amelia and Abigail Gabble, two British geese on vacation.
Goose took the cats to the outskirts of Paris, then set out to face their drunken Uncle Waldo.
Traveling across the city rooftops, the cats met O'Malley's friend Scat Cat and his musician, who performed "Ev'rybody Wants to Be a Cat".
After the band departed, O'Malley and the Duchess chatted on a nearby rooftop while the kittens listened on the window sill.
The Duchess' loyalty to Madame prompted her to reject O'Malley's marriage proposal. The next day, the Duchess and her kittens returned to the Madam's house.
Edgar finds it before the Madam finds it, and places it in a sack, deciding to send it to Timbuktu.
Roquefort follows O'Malley on Duchess' instructions, and O'Malley returns to the mansion, sending Roquefort to search for Scat Cat and his gang.
Although he had trouble explaining the situation to the alley cats, Roquefort managed to bring them in to help O'Malley.
O'Malley, the alley cat, and Frou-Frou fight Edgar, while Roquefort frees the Duchess and her kittens. At the end of the fight, Edgar is locked up in his own bag and sent to Timbuktu himself, never to be seen again.
Aristocat's family returned to Madame Adelaide, who, not knowing the real reason for Edgar's departure, rewrote her desire to exclude him.
After adopting O'Malley into the family, Madame established a charitable foundation, which housed the feral cats of Paris in the mansion.
Scat Cat and his gang are the first to enter, and repeat their song so loudly that the two hunting dogs can hear it in the countryside.
That's the story of The Aristocats.