 Shortly after his arrival from South America to New York, Steven Humbolt is found dead in his apartment at the Savoia Hotel. Inspector Decker Dawes (Conway Tearle) investigates the case and although the cause of death is described as apoplexy, Dawes is convinced it as murder, especially after he learns that Humbolt had been married fifteen times. The widows come from all over the world but three of them live in NYC; Sybilla Crum (Margaret Dumont), a noted evangelist; Carol Manning (Natalie Moorhead), recently remarried to a man named Arnold; and Ruby Cotton (Noel Francis.) A detective is sent to Philadelphia to try to learn the identity of the sender of a box of flowers delivered to Humbolt s room before his death. Dawes calls on Carol Manning Arnold, who says she had married Humbolt five years ago, and that he had disappeared after stealing all her money and she was told he had died in South America. But he had recently shown up trying to blackmail her as she had not told Arnold of the marriage. The autopsy shows that Humbolt was killed by hydrocyanic acid gas and that the broken glass globe, found by Dawes, was a Helmholtz resonator, a well-known device that can be broken by sound-waves. Sybilla Crum goes to the district attorney to try to stop the investigation, while Dawes also learns that, unknown to her husband, Carol maintains an apartment in her maiden name. Dawes hears a radio program featuring The Electric Voice (Ralf Harolde) in which the latter demonstrates the power of sound waves emanating from his voice in breaking glasses, ringing bells and other feats. When the Voice emits a sound that is supposed to break glass, a Helmholtz resonator on Dawes  desk breaks.