Psychiatrist Bartholomew Snow is called into a secret meeting with General Pratt, a U.S. Security Chief, and ordered to treat government scientist Arthur Vincenti, a former patient who has suffered a mental breakdown. Because Security fears an international ring of kidnapers who sell scientific geniuses, Vincenti is kept in hiding at a mysterious Base X in the Southern swamps, and Snow is blindfolded for each visit to his patient. Snow's life becomes more complicated when the scientist's sister, nightclub singer Victoria Vail (Vicky Vincenti), accuses him of abducting her brother. She causes an argument which leads to their arrest, and Snow avoids curious reporters by announcing their engagement. Snow is then visited by Fitzpatrick, a young man who claims that General Pratt is an enemy agent; Fitzpatrick reveals his true motives, however, by trying to force Snow to disclose the location of Base X. Snow realizes that he must remove himself from the case, and he recommends a substitute, but Fitzpatrick poses as the new psychiatrist and is taken to the base. Upon learning of the imposture, Snow, accompanied by Victoria, retraces his trips to the base by recalling sounds and the length of each journey. When he and Victoria arrive, they find both the scientist and General Pratt being held prisoner by Fitzpatrick. The ensuing battle is broken up by the arrival of the U. S. Army. Fitzpatrick and his men are captured, and Snow and Victoria are left to decide whether to remain engaged.