What's with Angus . . . and the Mona Lisa?!! Well, Angus is a cat, with ""French roots"" too, like owner Carol. And presently he's on a plane with Carol and her family, bound for Paris--when who should pop out of trunks in the baggage compartment but a male and a female thief, ""Pigeon"" and ""Turtle Dove,"" who plan to steal the Mona Lisa! When the plane lands, Angus follows the trunks to the cellar lair of the Baron, head of the thieving ring . . . and, by enlisting the cats of Paris, foils the theft. Then the cats surround the Baron, who's allergic to cats, and put him out of commission too. As for the vanished Carol-and-family, they see ""the whole story . . . on the TV news."" The sort of nonsensical rigamarole for which there's no excuse.