Although Charlie Chan's daughters appeared with him in previous films (including Charlie Chan in Honolulu (1938) and Charlie Chan at the Circus (1936)), this is the only film in which a daughter (Frances) plays the assistant role usually done by one of Chan's sons (Lee, Jimmy, Tommy).
Actress Frances Chan didn't have to stretch too far in this role. She played a character named . . . Frances Chan!
The thirty-third of forty-seven Charlie Chan movies.