The treasure is gold which Carruthers (Sidney Toler) has hidden away after faking the sinking of his ship. He has, in fact, tricked Mike and Jack into raising the sunken treasure for him, and then take it from them. Meanwhile a tropical storm is approaching and threatening to destroy the island...
Its an amiable enough though unexceptional film which drags at times. As the film was pretty low budget most of the "diving" scenes are obviously models. Seeing Sidney Toler not playing Charlie Chan is of course quite novel and probably the best part of the film. The final fights and the deadly storm are both pretty ridiculous. However, treated in the right way the film is enjoyable fluff.
