A team of two-fisted insurance investigators (one of whom disguises himself as The Masked Marvel) endeavor to discover and thwart the loathsome saboteur Sakima.

In ridding the area of muggers, the East Side Boys acquire a wealthy benefactor whose privileged son, unbeknownst to him, has fallen in with thugs.

Soon after a Chinese princess comes to the US to buy planes for her people, she is murdered by a poison dart fired by an air rifle.

A scientist is turned into an ape man.