While visiting the Keystone City Zoo, Jay, Joan and two Olympic champions are suddenly transported to another planet, finding themselves in the middle of an arena strangely like the Roman Coliseum.; Newspaper publisher Dale Thomas finds the body of a former fellow explorer in the newspaper presses in his plant. This man had once discovered a secret city in the jungles of the Amazon, and Thomas, accompanied by the Flash and Dr. Flura, are determined to find that city and rescue reporter Jim Ronson, no matter what the cost!; By a strange twist of fate, the personalities of a meek, mild-mannered bank clerk and a professional boxer are exchanged, a switch that keeps the Flash on his toes!