A well-known judge has become a fugitive from the police, with a large reward on his head. A reporter believes that the judge is hiding in a private sanitarium, so she seeks out a private investigator and asks him to pretend to be insane, so that he can get inside the sanitarium and look for the judge. The investigator is admitted to the asylum, and encounters many dangers while trying to prove that the judge is there.

Reporter Kathy Lawrence seeks the assistance of private investigator Ross Stewart in trying to locate Judge Finlay Drake, who is a fugitive from the law. Kathy has seen the judge's girl friend, Madge Bennett, visiting the La Siesta Sanitarium and suspects that the judge is being hidden there by sanitarium chief Dr. Clifford Porter. Kathy offers Ross half of the $10,000 reward money if he will pose as a patient, enter the sanitarium and confirm that the judge is there. Ross initially declines Kathy's offer, but after checking on Madge agrees to help her. Ross poses as Harry Horton, a manic depressive, and Kathy, posing as his wife, has him evaluated by a state psychiatrist and admitted to the sanitarium. He is assigned to a three-man ward and moves in with Quist and Purvis, who warns him about Dr. Porter and the poorly run sanitarium. When Ross attempts to enter a locked ward for violent patients, sadistic head attendant Larson stops him. In exchange for a substantial sum of money, Porter has given Drake a private room inside that ward but is beginning to worry about the risk he is taking. Kathy comes to visit her "husband," who has little to report, and gives him a concealed photograph of the judge. Later, as a punishment for criticizing the running of the hospital, Purvis is dragged away by Larson and beaten. When Ross sees Madge being escorted to the locked ward, he gives matches to Topper, a "fire bug," who starts a fire, affording Ross access to the locked area where he spots Drake. Dr. Porter thinks that Drake may accidentally have caused the fire and demands more money from him. The judge's photograph is then found among Ross's possessions, and Drake concludes that Ross is either a policeman or a reporter and tells Porter that he should not be allowed to communicate with his wife. The photograph is returned to Ross intact so that he will not suspect that they know about him. Larson then asks Ross to assist in cleaning the locked ward but, once inside, pushes him into a room and locks the door. Kathy, who is falling in love with Ross, is informed by Dr. Porter that her husband has been attacked by one of the violent patients and that she cannot see him. When Porter and Drake interrogate Ross, he tells them that his wife will report his "accident" to the authorities. Indeed, Kathy has confessed the deception and her fears about Ross's safety to the state psychiatrist, but he says he cannot help her. Consequently, Kathy arms herself with a gun and hides in Madge's car. In the meantime, Porter has confined Ross to the same room as a deranged ex-boxer who beats him up. Kathy then leaves Madge tied up in her car and, dressed in her fur and hat, gains entrance to the locked ward. Attendant Fred Hopps has meanwhile phoned for the sheriff to come. Kathy draws a gun on the judge and orders him to have Ross brought to his room. Ross then takes over and they try to escape. The ex-boxer attacks Larson but Porter shoots him. The sheriff's officers arrive and arrest the judge, Porter and Larson. After Kathy phones in her story, she and Ross embrace.