The Jade Mask is a 1945 film featuring Sidney Toler as Charlie Chan and the only appearance of Number Four Son, Eddie Chan, played by Edwin Luke, the real-life younger brother of Keye Luke, who had depicted Number One Son throughout the 1930s.
Plot
Charlie Chan, along with #4 son Eddie and chauffeur, Birmingham Brown, looks into the apparent murder of an eccentric scientist in a spooky mansion.
Although the scientist had been shot with a silenced pistol, further murders are committed with poison darts, with one narrowly missing Chan. Later, Chan discovers the dead scientist's huge collection of ventriloquist dummies are the key to the murders.