John Bowman, a wealthy farmer, is kidnapped one night after two mysterious men lure his car off the road. When the wreckage is discovered the next day, constable Russ Mason (Charles Sellon) forms a search party with Amos Rugg (Hallam Cooley) and Johnny Goodlittle (Johnny Arthur).
Amos and Johnny work at the general store in Danburg. They are in love with Betty Watson (Gertrude Olmstead), the storeowner’s daughter. Attempting to woo Betty, Amos invites her on a drive in the country. Meanwhile, Johnny has followed a mysterious stranger to the country. The strange man has lured Amos’ car off the road and kidnapped the couple. Johnny accidentally enters a hidden tunnel, and all three end up at Dr Edwards’ Sanitarium.
Once inside, they are greeted by Dr Gustave Ziska (Lon Chaney), who introduces Rigo (George Austin), Caliban (Walter James), and Daffy Dan (Knute Erickson), his patients. Ziska explains that he took control of the asylum after it had closed. After many attempts to expunge the three hostages, they are captured and sent to a dungeon, wherein Johnny finds Dr Edwards and John Bowman kidnapped by Ziska and his cronies.
Dr Edwards tells Johnny that Ziska, Caliban, Rigo and Daffy Dan were once his patients at the sanitarium. Ziska had been a great surgeon who went mad and began to perform unorthodox operations. He now intends to perform experiments on Betty and Amos, to discover the secret of eternal life.
Amos and Johnny are captured and brought to Ziska’s laboratory, where Betty lies fastened to a surgical bed. Amos is strapped to the “death chair” and connected to Betty through a transducer, which will exchange their souls. Johnny eludes Ziska’s henchmen and escapes to the roof, sending up flares which are seen by policemen investigating the wreckage of Amos’ car.
Having escaped, Johnny masquerades as Rigo and begins to assist the doctor. He frees Betty and Amos and straps Ziska to the death chair. Caliban appears and, mistaking the figure in the chair as Amos, activates the transducer, removing Ziska’s soul from his body. Because there is no one on the surgical bed, there is no soul to complete the exchange, and he is rendered lifeless.
Realizing his mistake, Caliban is distracted and Johnny captures him. The policemen enter the laboratory to find that Johnny has successfully apprehended the madmen and located the missing persons. This is enough to gain him respect as an amateur detective, and to win Betty’s heart and hand.
Roland West, Public domain, via Wikimedia Commons