The Menace (1918)

To prove his theory that environment rather than heredity determines a man's character, Dr. Burnell adopts young Richard, the son of an imprisoned crook Morgan. Upon graduating from college, Richard proposes to Virginia Denton, but several days before the wedding, Morgan appears and threatens to reveal himself as Richard's father unless the young man aids him in a number of robberies. Through Robert Hargraves, Dr. Burnell discovers Richard's part in the crimes and starts to believe that his theory is incorrect. When Morgan decides to rob the Denton home, Richard arranges with Dr. Burnell to trap them in the act, but it is Virginia who discovers the two rifling the safe, and she immediately breaks the engagement. After the police arrive, however, Morgan reveals that Richard is actually Dr. Burnell's son, kidnapped by Morgan at an early age. His name cleared, Richard marries Virginia.