Young Edyth Vail, believes her fiancé Allen Morris may have committed a murder, asking Ashton Kirk to investigate the crime. The fiancé admits he went to the David Hume's home to retrieve plans for a submarine, invented by his scientist father and stolen by the murdered man, but Allen claims he left the home before retrieving the plans. Kirk uses a train conductor's punch ticket to discover the identity of the murderers, one of whom is mute, and sets a trap to apprehend the suspects.

Ashton Kirk is a wealthy and scholarly young man who solves mysteries that have the police puzzled. Stella Morse asks Kirk to find out who is threatening her uncle, Dr. Morse. Morse has a copy of a secret treaty between Russia and the United States that was made during the Russo-Japanese War. When the Doctor is murdered Kirk takes on the case. Japanese spies have been trying to purloin the treaty to ruin relations between its country and America. Kirk manages to get the treaty himself and prevents a war from breaking out.