In a Mexican village, a team of Americans plan a trip into the mountains to search for an ancient treasure and two missing scientists. Charlie Chan stumbles into the case and joins their expedition, along with his number one and number two sons and chauffeur. Soon they are all tenting it, spying on each other and sneaking in and out of camp.
Bob Livingston is part of the search party but we soon discover that he actually heads a gang that's after the treasure. They have kidnapped the missing professor and are holding him in a secret temple whose hidden door swings open when you step on a certain big rock.
Roland Winters does okay in a fairly active role as the great detective. Keye Luke is a rather mature and serious Lee Chan. Victor Sen Young and Mantan Moreland, as Tommy Chan and chauffeur Birmingham Brown, are teamed up as usual to handle the comic relief. No explanation is offered for Keye Luke's surprising return to the series; we can only note that at the beginning of the picture the Chans are setting out on a family vacation, and guess that Lee must have been invited.
The plot is a little different from most in this series--we know who the villain is from early on. The production, of course, is cheap and the dialog seems hastily hashed out, although Mr. Chan does offer one or two of his wise sayings. ("Very difficult to estimate depth of well by size of bucket.") Overall it's really not very good...but enjoyable enough for fans.
Note: a fun double feature would be this picture preceded by 1937's Riders of the Whistling Skull. Not only is this Chan picture is a remake of that Three Mesquiteers western, but the earlier movie also featured Bob Livingston--as one of the good guys, in that case.
