Bored, millionaire brothers Randolph and Mortimer Duke (Ralph Bellamy and Don Ameche) make a wager on whether two people from opposite ends of the social spectrum can adjust successfully if they trade places. To this end, they engineer the rise of streetwise tramp Billy Ray Valentine (Eddie Murphy) and the fall of Louis Winthorpe III (Dan Aykroyd), a pompous yuppie who works for them on Wall Street. However, when the two guinea pigs find out what has happened, they join forces with smart hooker Ophelia (Jamie Lee Curtis) and loyal butler Coleman (Denholm Elliott), and plot their revenge.