Retired opera star Adelaide Bonfamille enjoys the good life in her Paris villa with even classier cat Duchess and three kittens: pianist Berlioz, painter Toulouse and sanctimonious Marie. When loyal butler Edgar overhears her will leaves everything to the cats until their death, he drugs and kidnaps them. However retired army dogs make his sidecar capsize on the country. Crafty stray cat Thomas O'Malley takes them under his wing back to Paris. Edgar tries to cover his tracks and catch them at return, but more animals turn on him, from the cart horse Frou-Frou to the tame mouse Roquefort and O'Malley's jazz friends.