After finishing up a case in Egypt, Charlie Chan goes to Shanghai with his Number One Son Lee for a well-deserved vacation. There's no rest for the weary, though, as Chan is recruited by the local police to help them topple an international drug smuggling operation. Aided by an American agent, yet somewhat hampered by the meanderings of his own son, Charlie Chan finally gets to the bottom of the case, ensnaring the smugglers and the criminal mastermind behind it all.