Jerry Lewis plays George Lester, an American in London, whose grandiose schemes constantly get him into trouble. His first outrageous plan turns his wife's ancestral palace into a Chinese disco, an idea she hardly appreciates. Forced to raise money to restore the mansion, George unveils an even crazier scheme with the help of his friend, William Homer (Terry-Thomas), to sell stolen plans for an electronic oil drill. George smuggles the plans into Lisbon where he is supposed to make the big deal, but then learns the plans are phony! He promises his wife he'll finally settle down, but wait -- he has just one more idea!