While working in the Stock Exchange building, plumber Michael Clancy makes a fast $200 when the calculations for his pipe-measurements are mistaken for a purchase of surging shares. Impulsively, Clancy decides to play the market and - somewhat improbably - becomes wealthy. The former pipe fitter abandons both his trade and his partner, Andy MacIntosh, to move uptown and enter high society. But whatever goes up must eventually come down, as Mike learns to his chagrin when the market crashes on Black Thursday, forcing him to reevaluate many of the decisions he has made.