In the small town of Midburg, alcoholic surgeon Dr. Bartley Morgan is ordered by Eddie Krator, "Public Enemy Number One," to remove a bullet from gangster Johnny Franklin. Reluctant to go against the law, but desperate for patients, Bart performs the surgery. The next day, Bart's faithful nurse, Margaret Hopkins, who secretly loves him, walks out after making Bart promise to stop drinking. Bart keeps his promise and uses Krator's substantial payoff to open a doctor's office in Manhattan, where he continues to operate on Krator's gang whenever there is a shootout, but refuses to help Krator's enemies and even turns them in to the police. At the same time, Bart builds up a clientele of New York's wealthy and becomes involved with Cynthia Weld, whom he plans to marry her for money. The F.B.I. gets involved in fighting Krator's gang and becomes suspicious when Monk Jackson, whom they believed they had fatally wounded, is picked up during a raid, completely healed. One night, Bayview Hospital calls Bart in to operate on a G-man at the same time that Krator needs him to save one of his men. Bart saves only the G-man and then sees Margaret at the hospital and rehires her as his assistant. An angry Krator issues Bart an ultimatum, but he blackmails Krator with information on his gang in order to be released from his commitment as the gang surgeon. Elmer Porter, ostensibly a harmless stamp collector, but really an agent for Krator who uses the name Evans, threatens to expose Bart to the Weld family, but Bart is undaunted, until his stocks drop and he needs $10,000 immediately. Meanwhile, F.B.I. agent Robert Anders asks Margaret to dinner, but is detained when Krator robs the Federal Reserve Bank. Krator escapes, but Franklin is wounded again. Bart accepts the medical job for a clean $25,000 and removes Franklin's bullet, but Franklin remains in critical condition. Meanwhile, a wounded guard identifies Krator and Franklin to Anders, and their names make the front page. Margaret finally realizes Bart's double life, and when Bart returns to the office drunk after the surgery, she again threatens to leave unless he returns Krator's money to him. Bart promises to return the money in the morning, but switches envelopes to deceive her. Margaret then calls the F.B.I. with an anonymous tip that Krator's hideout is the Ace Inn. Anders and his men raid the place and apprehend Franklin, on a stretcher, but Krator escapes. Franklin dies in the hospital without revealing who operated on him, but Anders notices that Franklin's old scar matches the scar Anders himself has from an operation performed by Bart. The next day, Anders finds his F.B.I. phone number on a memo pad on Margaret's desk and, when she swears she didn't call him, becomes suspicious. Anders then locates Krator in a small fishing town, and a statewide chase ensues until Anders, sure Krator cannot possibly escape New York, predicts that he will order Bart to perform a facelift. Krator arrives at Bart's office, and he agrees to do the plastic surgery with Margaret assisting, but she refuses and is tied up. Anders and his men arrest Bart and Krator, who is under anaesthetic, and Anders handcuffs Margaret to him for a dinner date.