Karen Lownes, a newspaper reporter, receives a phone call from a childhood classmate who urgently requests a meeting. When she arrives, Karen finds the man has been shot, but before he dies he tells her of a right-wing plot that is underway to assassinate three United Nations undersecretaries. Karen tells the story to a police lieutenant, Matt Lacey, but Lacey believes that the dead man was only a petty gangster and assumes that he was killed by his own associates. After Karen is attacked by a hoodlum anonymously hired to follow her, Lacey becomes convinced that the matter is to be taken seriously, and he doubles his efforts to uncover the plot. Karen follows a lead to a freight company office, where she inadvertently uncovers the identity of the assassins. The assassination is to take place at a diplomatic reception attended by the three undersecretaries, but Karen recognizes one of the men from the freight company, and Lacey arrests the would-be assassins.