Plumber Michael Clancy, fixing up some pipe on the stock exchange, accidentally buys some stock and makes a quick $200 on a 20 percent margin. He wants to continue but his partner, Andy MacIntosh, refuses to get involved. Clancy makes a fortune, leaves his business, and crashes high society, ignoring his old friend, and urging his daughter, Katie, to reject MacIntosh's son in favor of Freddie Saunders. Then the stock market crashes.