Mrs. Lean, the wife of a wealthy banker, loses her child and will not be comforted. Unable to endure loneliness longer, she adopts little Dorothy, an orphan, find as her husband has opposed such a move, she brings the child surreptitiously to the house while he is away. He returns home unexpectedly, goes to his library, unlocks the door of his private vault in order to deposit some very valuable jewels. At this moment, he hears childish laughter and rushes angrily out to investigate without stopping to close the door, Jennings, the butler (in reality a noted crook), has seen the gems and sneaks into the vault to look them over. The banker discovers his wife romping joyously with a little child, and insanely resenting the presence of the little one, orders her returned at once to the orphanage. Terrified at the thought, the little girl rushes away unnoticed, as the husband is remonstrating with his wife and hides herself in the library. Lean, after upbraiding his wife, bethinks him of the jewels and rushes back to the library, surprising Jennings in the vault. The banker is no physical match for the husky butler, who disarms him, overpowers him, and imprisons his master in a closet, rushing back into the vault to secure the gems. Little Dorothy is horrified over the situation, but dashes from her hiding place, slams the vault door shut, and gives the combination a turn. Then she runs for Mrs. Lean, who comes with her: they release her husband and call the police. Jennings is securely trapped with the goods and little Dorothy's heroism and wit so profoundly impresses the banker, that he signs the articles of her adoption and she becomes a member of their household.
—Moving Picture World synopsis