Prof. Jeremy, an eccentric old scientist, compounds a liquid which, if sprinkled on a person's face, will cause that person to speak the truth, and nothing but the truth. He first experiments on the cook, whose sweetheart, the policeman, hears her tell the professor that she gives him the professor's whiskey and cigars. Then the professor's daughter and her lover, Thorpe Willis, a young newspaper man, appear upon the scene, and Thorpe accidentally getting a spray of the liquid on his face, begins to lay bare his soul. The professor kicks Thorpe out and the next morning reads an account in the paper of his discovery, "Smoothy" Smithers, a crook, also reads the notice. The professor is finally so pestered by requests for the formula that he destroys it and locks the liquid in the safe. Smithers manages to get the liquid from the safe, but drops the bottle, allowing some of the liquid to sputter in his face. He then emerges from the house declaring to the world that he has just burglarized a house. The professor is finally so harassed by requests that he turns to Thorpe for help. The reporter writes up the whole affair as a hoax on the public and then is accepted as Jeremy's son-in-law.