One minute, Garfield and his pals are having a cookout, the next, they're engaged in a super battle with a sinister alien and her army of zombies. When an evil comic book demoness tries to make everyone in Cartoon World her slaves, all the comic strip characters become superheroes in order to thwart her. Well, everyone except Garfield that is. He thinks being a superhero sounds too much like work. But when he sees all his friends in trouble, the fat cat might have to rise to the occasion.