Simon Dayton is in fear for his life and seeks the help of Mr. Wong to protect him. Just prior to meeting Mr. Wong, Dayton is found dead in his office in San Francisco without a mark on him. Several witnesses testify Dayton was alone in his office that was locked from the inside. Though the police view Dayton's death as due to a heart attack, Mr. Wong discovers a broken glass ball that contained poison gas.
Among the suspects are agents of a foreign power wishing to stop Dayton's chemicals being sent to use on the foreign power in the form of the same poison gas that killed Dayton, Dayton's business partners who will have Dayton's share of the business come to them after Dayton's death and the actual inventor of the chemical who has been cheated out of profits and recognition by Dayton.
