Meredith Blake, a crook, reads in the morning newspaper that Professor Riem, a German scientist, is to arrive in the city on the 10:30 train that evening and is coining to purchase a valuable scarab from Robert Hamilton. He immediately plans to get possession of the scarab before the arrival of the professor. Blake and his three accomplices, Hortense, “Squint,’’ and the “Kid” make their headquarters in an underground room, which has only one entrance, a massive steel door. “Squint” is the only one who is capable of opening this door from the inside. Blake decides upon a plan. He procures a telegram blank and writes a message to Hamilton, stating that he will arrive at 8:30 instead of 10:30 that evening, and signs it Prof. Riem. The “Kid” then disguises himself as a messenger boy and delivers the telegram. After this the “Kid” disguises as an electric meter reader, and in this manner gains entrance to Hamilton’s basement, where he locates the switch, which connects the house wiring with the outside line. This switch happens to be within easy reaching distance of a ventilation hole in the side of the wall, so that one might easily reach in and turn off the power from the outside. That evening at 8:15 Blake goes to Hamilton’s home disguised as Prof. Riem. Hamilton, never doubting his identity, admits him to the living room, and proceeds to show him the valuable scarab. Blake writes out a fake check for $60,000, the price of the trinket. Hortense has been stationed at the ventilation hole outside with orders to turn the lights off for a few seconds at 8:30 sharp. The “Kid” was to call Hamilton’s number on the telephone also at 8:30, so that Blake would know exactly when the lights were going out. The lights are extinguished for just a few moments, and when they are again turned on, the scarab has disappeared. Blake pretends that he is angry, and demands that they all be searched, including Hamilton’s daughter, Judith, who has just entered the room. He then rushes out of the room in a fit of fury, declaring that Hamilton intended taking his check, then stealing the scarab. Hamilton is perplexed, but when the butler tells him that the caller wore a wig and false mustache, it is clear to him. He has been robbed. Just at this moment, Richard Neal, Judith’s sweetheart, comes to call. He is told of the extinguishing of the lights, and the mysterious disappearance of the scarab. He immediately leads them to the basement, where he finds a finger-print on the handle of the switch. He removes the handle, and after carefully protecting the finger-print, places it in his pocket. The next day, Hortense, Blake’s stylish looking accomplice, approaches a stranger on the street and inquires where she can find the Hamilton residence. This stranger was no other than Richard Neal, who was more than glad to show her to his sweetheart’s home. She explained that she was an old schoolmate of Judith’s, and would like to see her again. Judith does not recollect any such person, but out of politeness, asks her into the living-room, where she meets Mr. Hamilton. Hortense sits in the large leather chair, which Blake occupied the night before, and when Hamilton dropped his eye-glasses, it offered her a splendid opportunity to reach under the chair and get the scarab, which lay on a small ledge. While picking up the glasses with one hand, she clutched the scarab with the other and slyly placed it in her purse. Instead of handing the eye-glasses back to Hamilton, Neal held out his hand and she placed them in his hand. He had a purpose in doing this, and after carefully placing the eye-glasses in his pocket, bids them good-bye. Hortense very shortly makes a graceful departure, but Judith is suspicious and follows her. They arrive at the great steel door of the dungeon and after Hortense enters, Judith forces her way after her. She is handled very roughly, and is thrown into a room where the “Kid” is left to guard her. She pleads with him to release her, and he thinking that she will never come out alive, opens a trap door, which will admit her to a sewer, and tells her this is her only chance of escape. She enters the sewer and wanders for hours in the dark passage. When the “Kid” tells Blake what he has done, he is knocked down and thrown out bodily. In the meantime, Neal has discovered that the finger-prints on the eye-glasses and those on the switch handle are identical, and rushes back to the Hamilton home, where he is told of Judith’s disappearance. He and Hamilton immediately start in search of her, and while walking down the street, are attracted by a large crowd assembled around a manhole. As they approach, they are horrified to see Judith emerge from the dark hole in the street, ragged and dirty. Some laborers had lowered a ladder, for the purpose of doing some work. Judith happened to be near and made use of it. The “Kid” happened to be in the crowd, so planning to get square, he leads Judith, her father and Neal to Blake’s headquarters. The “Kid” knocked, giving the signal for “Squint” to open the door and when it was opened, all four rushed in. A terrible struggle then takes place, in which Neal. Hamilton and Judith are overpowered, and after being bound, are thrown into a dark room. The “Kid” again receives a beating and is thrown out. He rushes and tells the police, who arrive very shortly, and blow open the steel door. Another fight then takes place, but this time Blake and his band are taken prisoners, and the scarab returned to Mr. Hamilton.