The Prince of Pep (1925)

Dr. James Leland, a wealthy and philanthropic young physician who inherited his father's fortune, spends much of his time entertaining children in New York City hospitals. His secretary and business manager, Hugh Powell, also inherited from his father, is secretly allied with dope peddler Buck Sanders. Assisting Hugh is Ruth Wheeler, Dr. Jim's unfaithful fiancée. When Dr. Jim catches his secretary stealing drugs, Hugh knocks him unconscious and, believing he is dead, dumps him in the river. Dr. Jim regains consciousness but loses his memory and develops a dual personality: first as "Jimmy," who assists Marion Nord in running her father's East Side medical clinic, then as "Black Flash," a mysterious bandit who supports the clinic by robbing wealthy gamblers. Hugh bribes Buck and his men to kidnap Marion, but Jimmy becomes aware of the plot. The police arrive to apprehend the culprits, but not before Jimmy is again knocked unconscious. Dr. Jim recovers his memory and returns to his rightful place in society with Marion by his side.