Charlie Chan at Treasure Island (1939)

The more effective pairing of "Charlie" (Sidney Toler) and No 2 son "Jimmy" (Victor Sen Yung) are embroiled in an investigation into an apparent suicide of his friend "Paul" (Louis Heydt) on a plane to San Francisco. It soon starts to look like there is much more too it to - the last page of a manuscript he was working on has gone missing - and investigations lead them to the door of the mysterious "Dr. Zodiak" who claims enormous psychic powers. What ensues now is quite a cleverly constructed mystery with loads of mystic hokum, some blackmail and a good supporting cast from the likes of Pauline Moore ("Eve") and Cesar Romero as rival mind reader "Rhadini". The tension for this entertaining drama is really helped by spooky scenarios and the somewhat menacing costume of the enigmatic "Zodiak" - indeed quite a bit of effort has gone into the production culminating in quite a surprising conclusion involving an old iron maiden. One of the best of the series.