The hills of Virginia are home to the most elegant steeplechases. But after a competitive run, a jockey is found stabbed to death. The knife in his chest impales a queen of clubs, and when a second jockey is murdered, he is decorated with the queen of spades. Now it's up to racing judge Mary ("Harry") Haristeen and her sleuthing cat, Mrs. Murphy, to hunt down the culprit before the queen of diamonds appears.