[2][3][4] The serial sees Captain America, really District Attorney Grant Gardner, trying to thwart the plans of the Scarab, really museum curator Dr. Cyrus Maldor—especially regarding his attempts to acquire the "Dynamic Vibrator" and "Electronic Firebolt", devices that could be used as super-weapons.

[5] In a rare plot element for Republic, the secret identity of the villain is known to the audience from the beginning, if not to the characters in the serial.

A rash of suspicious suicides among scientists and businessmen, all found holding a small scarab, gets the attention of Mayor Randolph.

He demands that Police Commissioner Dryden and District Attorney Grant Gardner get to the bottom of the case, while openly wishing that Captain America, a masked man who has helped defeat crime in the past, were around to solve the mystery.

Gail Richards, Grant Gardner's secretary, investigates and realizes someone knows of the "Purple Death", a hypnotic chemical responsible for the suicides.

[1] Captain America was written by seven of the top serial screenwriters, including Harry Fraser’s only work at Republic.

Timely, the owner of Captain America, was unhappy with the omission of Steve Rogers, the lack of an army setting and his use of a gun.

Republic responded in writing that the sample pages provided by Timely did not indicate that Captain America was a soldier called Steve Rogers, nor that he did not carry a revolver.

Film historians Jim Harmon and Don Glut speculated that the script was originally written as a sequel to 1940's Mysterious Doctor Satan, which featured the masked hero The Copperhead.

[7] Dale Van Sickel was the "ram rod" of the stunt crew, doubling Dick Purcell as Captain America.

[1] The serial was re-released on 30 September 1953, under the new title Return of Captain America, between the first runs of Canadian Mounties vs. Atomic Invaders and Trader Tom of the China Seas.

Captain America is regarded as the "apex of the traditional action film fight...[in the] opinion of many cliffhanger enthusiasts".

Steve Rogers' ex-girlfriend in the Ultimate Marvel continuity is named after Gail Richards, Grant Gardner's secretary.

The 2011 Marvel Cinematic Universe (MCU) film Captain America: The First Avenger features the title character starring in a serial early in his career.