Harrison Craig, secret service agent, is on the look-out for a noted diplomatic criminal known as H. I. J. Craig goes to the Marbourgh Hotel, registers as H. I. J. and goes to room 309. The Countess goes to the room and delivers some valuable papers. H. I. J. arrives, sends for the Countess and she realizes she has delivered the papers to the wrong man. Craig takes the Countess into a taxi and drives her to Fort McPherson where she is compelled to remain. Craig has taken a card from her purse reading, "The Door with the Iron Ring." He goes to a cellar, pulls the iron ring and a bell resounds. H. I. J. pulls the door open and Craig falls into the cellar. There is a fight in which Craig finally overpowers H. I. J. and takes him prisoner.