When Paris agent Nardi (Dorothy Appleby) is stumped by the presence of an international counterfeiting ring she calls in the legendary detective Charlie Chan (Warner Oland). However, before Nardi can explain the clues she has already uncovered someone murders her. Now it is up to Charlie and his number one son Lee (Keye Luke) to figure out the puzzling pieces that Nardi has left behind. The father – son duo have to put their heads together and unravel the last message from Nardi. Just as success is imminent, chaos breaks out and Charlie and Lee find themselves running from the crooks. However, just as it seems that the pair will be caught and also murdered, the cards are turned and the counterfeiters are captured with the help of the French police.