Desc: The House of Mystery: Andrew Garfield, a banker, disowned his son for marrying beneath his station. He learns of his son's death and regrets his action. He determines to locate his son's widow and child in order to repair to some extent the results of his harshness. He advertises for them in the newspapers. The child chances to read the advertisement. Her mother decides to call on the banker, but has no suitable apparel. She writes a note to a neighboring family, asking for a loan, explaining the circumstances. These people, however, are a set of rogues, and take advantage of her confidence. Under pretense of helping her, they make her and her child prisoners and lock them in a wretched cellar. The woman then passes herself off to the banker as the widow whom he is seeking. Having been installed in the banker's home with her child, she succeeds in admitting her husband and her brother under the guise of servants. Puzzled by a series of thefts, the banker calls in Nick Winter, a famous detective. He disguises himself as a doctor, and calls for the intended purpose of treating the supposed widow, who has feigned an attack of paralysis. One night Nick finds Garfield drugged. He hides himself in the room and sees two masked men and a heavily veiled woman enter. He holds them up at the point of a gun, but they escape after switching off the electric lights. Then follows a series of remarkable escapades. Nick finds a note in his room advising him that he has been recognized and threatening him if he remains. He puts a dummy in his bed and sets an automatic picture camera to take the picture of any intruders. The robbers enter and attack the dummy, which they suppose to be the detective. He rushes in and captures both men. Then he brings in the banker to show him the prisoners. But again they have escaped. Nick takes the camera and develops the film, which shows him the prisoners being released by the mysterious woman. He recognizes the servants and proceeds to trail one of them. The trail leads to a tavern where the robber gives Nick the slip by a clever ruse. He steals a wagon and drives off. Nick gives chase but to all appearances the robber escapes and drives to the house where the real widow and her child are prisoners. Nick crawls out of the wagon in which he had hidden, captures the thief and rescues the captives. He then returns to the banker's home in another disguise. The thief makes his escape and returns to warn the others. Nick and the old man are made prisoners and placed in a dungeon of the old house. Learning of a secret contrivance for flooding the dungeon with sand, the robbers set the machinery in action. Soon the prisoners realize that they are doomed. Writing a note to the police. Nick fastens it to a pigeon which he had concealed in his hat, and releases it. The police get the note and arrive just in time to rescue the men and capture the robber band, who are this time sent to prison.