Perry Mason and Della Street are approached by a young secretary, Susan Fisher, who needs help after discovering that her boss may be involved in some fishy matters at the Corning Mining, Smelting, and Investing Company. A shoe box full of money and the company's owner both disappear, and Miss Fisher finds herself needing Perry Mason's assistance even more. When the manager of the Mojave Monarch Mine ends up murdered, Mason has to draw on all of his expertise to prove that his client didn't commit the deadly crime.