Colonel Bentry hires private-eye Belinda Prentice to investigate his stepson and heir Bill Forestman. Bill has withdrawn large sums of money from his account, according to the Colonel, rented an apartment in the city and stoutly refuses to explain his actions. On their way to the Bentry estate, Belinda and her assistant, Iggy Broty, stop near Bill's apartment and their attention is attracted by two suspicious-looking characters. Iggs stays to check them out while Belinda goes on to Bentry's. She is admitted by Severance, the butler, who goes to the library to announce her arrival. She hears a cry from Severance, goes to the library and finds the Butler standing over the dead body of his employer. Belinda picks up a hypodermic needle lying near the body. Inspector Prentice of Homicide, Belinda's father, arrives to take over. He questions Bill, his sister Judith Forester, Jonathan Lowell, the family lawyer...and Severance, who confesses that he is a reformed drunk AND a disbarred lawyer. Belinda leaves and confers with Iggy, and learns that the two men in front of Bill's apartment house were Professor Ordoson and "Chicago", Bill's personal bodyguard. Iggy "visits" Bill's apartment and is beaten up by "Chicago." Belinda makes a formal call on Bill, and Bill is most cooperative and he explains that he and Ordson are working on a secret-but-harmless experiment; that "Chicago" is employed to protect their material and equipment; and that he HAS NOT withdrawn large sums of money from his account. Belinda, highly satisfied by Bill's explanation, decides she and Iggy will follow her number two suspect---Judith. They find her in a downtown bar where she is plying the family butler with liquor. Belinda finds this interesting but has another surprise awaiting her when she returns to her office and finds Lowell and "Chicago" there, and Lowell's intention is for Belinda to leave town for a while and has asked gun-for-hire "Chicago" to accompany him there so Belinda will grasp the seriousness of his get-out-of-town request. So, on a hunch, Belinda goes with her father to the Bentry estate---where they find Lowell dead on the lawn. It is at this point that Belinda provides the solution to all that has been transpiring