The Ace of Spades Reveals Your Death!
Crime novelist Neil Broderick (Chester Morris) is investigating the serial killer "Mr. Ace," so named because he sends his intended victims an ace of spades announcing the time of their murder in advance. Never one to miss a scheduled appointment, Mr. Ace stumps bumbling police investigators Clancy (Frank McHugh) and Dugan (Allen Jenkins) as he fiendishly slaughters victim after victim with a thin, sharp instrument of death.
Industrial magnate Austin Winters receives Mr. Ace's death card. He boards an airplane hoping to escape his appointment with death. Thousands of feet above the earth, however, the lights go out at 7 p.m., and when they snap back on moments later, the survivors are baffled by the mystery of a mid-air murder!