Two hard working professors succeed in creating a process to enlarge the size of living organisms, but when they choose to try the process on human beings, and succeed with dreadful results, the Man of Steel must intervene.; Warned by a friend of his of 5th Columnists landing by boat in the city of Metropolis, Clark Kent, as Superman, investigates and discovers that they are planting skilled workmen as spies and saboteurs with American armament factories, as well as having a secret base in a mountainous valley, complete with a subversive army capable of striking terror and destruction from the rear when U.S. military forces are attempting to defend coastal areas against foreign invasion.; After Clark is fleeced at a local carnival, Lois is given permission by the editor of the Planet to get evidence of the crookedness of the games there and ends up discovering that the carnival also has pickpockets roaming the grounds, robbing the guests.; Lois and Clark attempt to get the low down on thefts of morphine, as well as trying to prove the guilt of a lawyer who manages to get his clients freed in court on technicalities.