A mysterious visitor is found murdered in Mr. Wong's study in this, the third of Monogram's low-budget thrillers, featuring
Hugh Wiley's Chinese detective. A startled Wong (
Boris Karloff) learns from enterprising girl reporter Bobby Logan (
Marjorie Reynolds) that the murder victim is Princess Lin Hwa (
Lotus Long), in San Francisco to buy airplanes for her brother's army. Both the princess' traveling companion (Bessie Loo) and a mysterious dwarf (
Angelo Rossitto) become victims of a mystery killer, who uses an ancient Chinese dart as his weapon of choice. The trail leads to a steamer in the San Francisco harbor, whose captain, Jalme (
William Royle), is highly suspicious. Also among the would-be murderers are a phony airplane manufacturer (
Peter George Lynn) and a local banker (
Huntly Gordon). Although kidnapped by Jalme, Mr. Wong manages to unmask the real culprit. ~ Hans J. Wollstein, All Movie Guide