Hapless hardware salesman Marty Sloane decides he's going to do the convention thing, and score himself a nice looking lady. But she's actually a high class prostitute, and worse than that, she's stolen something from mobster Charlie Bombay. Bombay interrupts the pair while Sloane is still working up his nerve. From a hiding place, Marty watches Bombay pitch the girl over a balcony to her death. Now Sloane has the key - literally and figuratively - to putting Bombay away for a long time. But revealing what he knows would cost him his reputation back home. And then Bombay learns who he is and what he saw...