Dr. Hubert Bolling and his young partner, Clinton Wayne, are together in consultation. The doctor advanced a theory to the effect that seemingly hereditary tendencies are developed only when the child realizes the traits to which the parent is given. To this theory young Wayne takes exception. Nadine Powers, the young girl to whom Wayne is engaged, is the daughter of Randall Powers, a wealthy man, whose source of income is ostensibly from certain investments in the west. At this time a series of daring thefts and bank robberies take place in the city and are seemingly the act, or at least are under the supervision of one brain. Detectives are assigned to the case and eventually a clue is discovered. Dr. Bolling is an intimate of Powers. Powers shows him his strongbox and tells him that, should anything unexpected happen to him that he, Bolling, will become the guardian of Nadine and will find all necessary papers in the box. Bolling agrees to Powers' request to care for Nadine under such circumstances. The detective bureau's trail leads directly to Powers as the mastermind, but he is not apprehended before he has had ample warning. Realizing that the game is up and rather than serve a prison term, he commits suicide. Wayne is visiting at the house when Powers shoots himself and at the same time he and Nadine find the body the detectives enter. Nadine, unknown to Wayne, hears enough of their conversation to acquaint her with her father's past. Dr. Bolling takes charge of affairs. Wayne explains to him what he has learned of Powers' life and they determine to ,eep the matter from Nadine. She, however, has learned sufficient. She is horrified with the knowledge that she is the daughter of a criminal and the thought preys upon her. The effect of Nadine's secret thoughts is reflected in the temptation to steal, which grows gradually stronger. Eventually she succumbs to kleptomania, steals from a store and then, though not caught, undergoes bitter remorse. "It is useless for me to battle against the inevitable. I am the daughter of a criminal and have inherited the instincts of one," she tells Wayne. Despite his pleadings she insists upon breaking their engagement. Dr. Bolling's aid is sought by Wayne. He listens to Wayne's statement and when it is finished tells him the whole affair is absurd. Powers' papers have been examined and he has learned that Nadine was adopted by him. Wayne hastens to Nadine with the news. Nadine recovers from the effect of her morbid fancies. Wayne and she are happily married and Dr. Bolling resumes his practice. Wayne, however, visits him one day and cannot help remarking that his wife's case has proven beyond a shadow of a doubt the correctness of his theory upon inherited characteristics. "If Nadine," he says, "had really been Powers' daughter, no power upon earth could have saved her." Dr. Bolling gravely admits Wayne's statement, but as he leaves he turns to his colleague, who has overheard the conversation, and tells him that, while he can never tell Nadine or Wayne, the papers in his possession prove Nadine to have actually been Powers' daughter. He shows the certificate of Nadine's birth.