She went out on the yacht's deck at midnight, Friday the 13th, clad in only a flimsy nightgown—with a gun. Her faithless husband gasped, clawed at the air, fell overboard and vanished. His green-eyed girlfriend denied he had been in her cabin. Every piece of evidence screamed that Marion Shelby had murdered her husband—which only reinforced Perry Mason's stubborn hunch that the young wife was innocent. But by the time the trial was in session, he still had nothing to go on...