Charlie Chan (Roland Winters)

Princess Mei Ling pays a visit to the Chan residence, where upon being admitted by man-of-all-work Birmingham Brown she refuses to give her name, but hands Birmingham her ring to show to Charlie. While Chan is being summoned, a mysterious figure shoots a dart at the beautiful Princess who manages, before she dies of poison, to scrawl the name "Captain K" on a handy piece of paper. When the police arrive, Charlie has to admit that he does not know the identity of his murdered visitor, but that he means to find out. What he learns is that Mei Ling has brought with her to America the sum of one million dollars, in order to buy airplanes for the Chinese struggle for freedom. Someone has stolen the money, and someone may be trying to divert the planes into enemy hands. Can the famous detective, despite the fact that his Number Two Son has unaccountably changed his name from Jimmy to Tommy, who used to be his Number Three son, and despite the fact that Charlie, who used to be a Honolulu Police Detective, and then a Honolulu Police Detective On Loan To The United States Secret Service, has not only lost his jobs, but also the rest of his large family and has moved to San Francisco, discover who the bad guys are and solve the case?

The LaFontanne Chemical Company is shipping out a load of we're not sure what, disguised as something entirely different. Mr. Pereaux and Mr. Grock don't want that shipment to ever arrive anywhere, and they and a man named Aquirre mean to stop it at any cost. The ship's owner, Mr. Fontanne, smells a large rat and calls Chan in on the case, since the famous detective is in New Orleans because, well, because he felt like being in New Orleans, I guess. Chan gets what facts there are from LaFontanne, who is promply set upon by a gang who attempt to kidnap him, but fail. Mr. LaFontanne's partners come up with some insurance; just by chance they tell him, a partnership agreement (why they would have been running a company all this time without one is another large mystery which will not be solved) that bestows upon the living partners the portion owned by a deceased partner. Then the guy who invented the formula for the poison gas that the company is making but who was, in his opinion, swindled out of his rights to make a profit from it, shows up and threatens LaFontanne with a gun. Well, he turns out to be a harmless crank. Or is he? Everyone seems suspect, clues are boundless but don't seem to fit into any particular pattern or too many patterns, take your pick. But Chan must solve the mystery before Monogram is depleted of out-of-date film stock. Can he?

Vic Armstrong arrives at his Uncle Judge Armstrong's home just in time to answer the telephone. Unknown to him, his uncle has just been murdered and the culprit is right there in the room with him! Phyllis Powers, on the other end of the line, recognizes Vic's voice, but just then Vic is knocked unconscious by the murderer. When he awakens, he (for reasons known only to movie mystery writers) pulls the knife out of his uncle's back, thus putting his fingerprints all over it, and just in time for the police, having been called by a worried Phyllis, to discover him standing over the body. Well, we know he didn't do it, but the police don't agree. Can Charlie Chan recognize the boy's innocence, and find the real murderer before Vic is sent into durance vile, or even worse?

A gold mine in Arizona, that was formerly losing a lot of money, suddenly turns into a veritable money-making machine. However, the owner, instead of being happy about his now profitable business, insists to Charlie that something is fishy and that someone is out to murder him. Charlie and his "crew" travel to the mine, pretending to be tourists staying at a nearby dude ranch so as not to arouse suspicion, and discover that the owner may well be right--it looks like the mine is being used as a cover for criminal activities, and that someone is indeed out to murder him.

In order to learn the location of a fabled Aztec treasure, a professor kidnaps his colleague, the only man able to read the ancient Aztec script that is supposed to reveal the location of the treasure. Charlie Chan and his #1 and #2 sons journey to the jungles of Mexico to find the victim and bring the kidnapper and his gang to justice.

All the passengers on an airplane headed for San Francisco are drugged, and when they wake up, it is discovered that a quarter-million dollars is missing. Charlie Chan--and, of course, his #1 son--must discover the identity of the person who doped the passengers and stole the money.