Below is an advertisement [Dramatic Mirror September 21, 1918] from my personal collection advertising that the Houdini Serial [AKA The Master Mystery] will be released on the open market plan.
The Master Mystery was released on the open market plan in November of 1918.
The first four episodes was first shown at a special trade show on November 7, 1918 at the Strand Theatre in New York City.
And it made its premier, November 18th, 1918 in the Saint James Theatre in Boston.