Garfield, the fat, lazy, lasagna lover, has everything a cat could want. But when Jon, in an effort to impress the Liz - the vet and an old high-school crush - adopts a dog named Odie and brings him home, Garfield gets the one thing he doesn't want. Competition.

Jon and Garfield visit the United Kingdom, where a case of mistaken cat identity finds Garfield ruling over a castle. His reign is soon jeopardized by the nefarious Lord Dargis, who has designs on the estate.