Popeye, Olive Oyl and more King Features Syndicate comic strip characters are invited on a cruise hosted by Professor Grimsby, a mad scientist who wants to eliminate laughter from the world. When the ship is held hostage on his island lair, it's up to the much more action-inclined Mandrake the Magician, Steve Canyon, and Flash Gordon (among others) to save the funnymakers from their eternal inprisonment.