Gangsters, put out of business by repeal of Prohibition, find a chemist to counterfeit drugstore products.
Norma (Bette Davis) works in a neighborhood drugstore and asks owner and boyfriend Jimmy Morrell (Charles Farrell) to make it a real store. Lefty (Allen Jenkins) tells Norma to get Hercules beer; but his boss Dutch Barnes (Ricardo Cortez) finds too much competition now that beer is legal. Jimmy fixes him an aspirin substitute and says he can make good toothpaste too. Barnes gives his men Jimmy's toothpaste and the name brand, and they argue which is better. To save on advertising, Barnes manufactures toothpaste using the brand name. His gangsters force the druggists to buy cases of it. Barnes is collecting money, and his girlfriend Lil (Glenda Farrell) suggests they make women's compacts, perfume, and powder. Barnes puts Jimmy to work on it, but Norma complains to Jimmy that the toothpaste business is crooked. While Barnes is trying to send Lil off to Europe, Mae comes in and fights with Lil. Barnes is cut and sends for Jimmy, who gives him an anti-septic. At first Jimmy refuses to make anti-septic without boric; but Barnes gives him $1,000 so that Jimmy and Norma can get married.
Lil tells the board of directors of Odite Co. about the racket, and they sue Barnes. Odite president Sheffner (Henry O'Neill) goes to Jimmy, who agrees to quit and tells Barnes. Lil asks the district attorney for protection; but Barnes has Jimmy take Higgins to Lil's place, where Higgins murders her. Barnes warns Jimmy not to call the police or leave. Learning about digitalis injections for heart trouble, Barnes asks Jimmy to make a phony digitalis. Jimmy refuses; but after Barnes has him tortured and threatens to call pregnant Norma, Jimmy gives in. The Odite directors vote for bankruptcy, protected by their preferred stock. Sheffner objects and contemplates suicide. A doctor tells Jimmy he may have to give Norma digitalis. Jimmy tells him to wait and goes to get some; but Norma loses the baby, because the heart stimulant did not work. Jimmy goes and shoots Barnes, whose body falls into acid and dissolves. Jimmy turns in the gang. He confesses and is exonerated, but the gang gets twenty years. In the final scene Jimmy and Norma are happy running their neighborhood drugstore.
This story shows Prohibition's criminal element adapting to changing times. Their unethical greed corrupts Jimmy's chemical skill. Experiencing the harmful consequences causes Jimmy to commit murder and go to the police.