Khan goes after a mysterious swordsman, wearing the mask of a secret Chinese society, who has murdered a wealthy San Francisco manufacturer and threatens the dead man's partners. The victim was accused of causing a fire that cost the lives of a number of Chinese workers.

Ohn Chang, an overwrought father hires Khan to find the man who murdered his daughter.  Keye Luke guest stars on Khan (Khigh Dhiegh) as a disconsolate father, convinced that his daughter's death is the doing of a young medical intern. Ohn Chang (Luke), unaware of his daughter's dissolute life, seeks Kahn's help in establishing the doctor's (David Wilson) guilt.

Khan undergoes some pangs of conscience when a former British agent stands accused of diamond robbery and the evidence is overwhelming. The man saved once Khan's life.