Charlie Chan (Sidney Toler) has come to Mexico City, to see to it that
a new formula for an all-powerful atom bomb doesn't fall into the wrong
hands. Then though, the secretary (Donald D.Taylor) of the scientist
(Robert Emmett Keane) who has developed the bomb is murdered, and later
the scientist himself. There is evidence though that the formula has not
been stolen, even though nobody knows where it's hidden. There is a heap
of problems though surrounding the two murders: The hotel the two stayed
at is full of enemy spies on one hand, on the other, both men were killed
by a gunshot, and in each case only one shot was heard - yet two
cartridges are found at each crimescene, and weirdly enough, evidence
suggests none of them were fired from guns at all. So what was the murder
weapon, who did it, where's the formula, and what has a bottle of Chinese
ink to do with all of this.
During their investigations, Chan and local
inspector Carvero (Fortunio Bonanova) seem to be getting nowhere for the
longest time, and only stumble upon more and more corpses, all killed by
gunshots from no guns - then Charlie finds a weird object someone has
slipped into his pocked, an object that's clearly made of two bullets and
some device that's remote controlled. Shortly afterwards, the device goes
off, and it would have killed Charlie would he have kept it in his pocket.
So that's the murder weapon, and a cryptic message the dead secretary has
written with his dying breath reveals the remote control to be a fake
thermostat that the killer simply applied wherever he wanted to kill
somebody, as it would look inconspicious enough. Now though Charlie finds
one of this thermostats, sets it off, and just follows the sound of the
gunshots to the killer's (Barton Yarborough) room, where all the devices
go off one after the other. The killer was of course a foreign spy and
gunrunner - but that leaves one question unanswered, where's the formula?
that's where above-mentioned Chinese ink comes in, it was written almost
invisibly onto a typewriter ribbon and this way kept out of everyone's
sight though it was in plain sight ...
Benson Fong plays Charlie Chan's
prerequesite son, while Willie Best replaces Mantan Moreland as Charlie's
chauffeur - and proves to be no match for the talented Mr Moreland.
of the lesser Charlie Chan-movies, mainly because on one
hand Chan doesn't really sit well with larger-than-life espionage plots,
on the other because the mystery at hand including the murder weapon is
just a bit too far-fetched even in the genre-context to remain believable.
Add to this that the mystery and the humour aspects of the film are not as
balanced out as in other Chan-movies, and you end up with
... something not very good, actually.