An arrogant socialite Bently (Louise Henry) is found dead in Reno hotel, with Mary Whitman (Pauline Moore) standing over her though she protests her innocence. Her husband Curtis (though Mary had gone to Reno to get a divorce) asks Charlie Chan (Sidney Toler) to travel to Reno to help prove Mary's innocence...
Charlie investigates a complicated case involving mysterious visits to mines, acids, crooked doctors and many suspects. Quite a few people had motive to kill Bently. If not Mary then was it the hotel manager (Phyllis Brooks) who has a crush on Doctor Ainsley (Ricardo Cortez) who has his own dark secret?
With the help of his son (Victor Sen Yung) and the rather more dubious help of the sheriff (Slim Summerville), Charlie unmasks the true culprit, and the Whitmans also have a happy reunion. One of the better entries in the long series (though none of the Charlie Chan films are bad).
