In the Masked Marvel, a group of saboteurs, led by Japanese agent Sakima, is trying to halt America's war materials production.  They engage in all sorts of sabotage.  One insurance company brings in four investigators to try and stop the destruction, since they are the ones that pay for all of the damage caused by Sakima's agents.  Helping the investigation is the Masked Marvel, who is secretly one of the four investigators.  Also helping the investigators is Alice Hamilton, daughter of the owner of the insurance company.  Mr. Hamilton is killed in the first chapter by Mace, the number one field agent for Sakima.  Also helping Sakima is Mr. Crane, who is highly placed in the insurance company.  Mr. Crane has a trap door which allows him access from his office too the basement, which is secretly the lair of Sakima.  And now, on with the movie.
 

Sakima's henchmen are pouring a highly flammable liquid known as Nitrolene into a storage tank containing lend-lease gasoline.  When the gasoline is used in airplanes, they will explode, destroying the Allied air forces.



The Masked Marvel arrives in time to prevent the villians from completing their nefarious scheme.  He battles with one of them on top of the storage tank.



Mace decides to eliminate the Masked Marvel and the gasoline at the same time by lighting fire to the delivery truck containing the Nitrolene.



  As the fire burns out of control, the Masked Marvel is knocked off the top of the storage tank . . . .



. . . . and crashes through the canvas top of the truck.



  . . . The truck explodes in flames.  What will become of the Masked Marvel?

You'll have to wait until next week to find out!!