Executive Producer: Gene Roddenberry
Producers: Gene L. Coon + John Meredyth Lucas
Associate Producer: Robert H. Justman
Script Consultant: D. C. Fontana

Writer: John Meredyth Lucas
Dir.: Vincent McEveety

Captain Kirk: William Shatner
Science Officer, First Officer, Cmdr. Spock: Leonard Nimoy
Dr. Leonard "Bones" Mc Coy: DeForest Kelly
Lt. Sulu: George Takei
Lieutenant Commander Montgomery Scott: James Doohan
Lieutenant Uhura: Nichelle Nichols
John Gill: David Brian
Malekon: Skip Homeier

Stardate 2534.0

The Enterprise is approaching Ekos as they are suddenly fired at. The population of Ekos is known to the Federation, but definitely not as far developed as possessing atomic missiles like the ones they were shot with. Kirk and Spock get beamed down onto the planet, dressed as the people they expect to meet, trying to find out what has happened to the Ekotians. After an encounter with a Zeonist, who warnes them and strongly advises them to hide, before being found, kicked, beaten, called names and finally arrested by an army–like group. A close look reveals the insignia of Nazi – Germany officials. This incident convinces Kirk and Spock to get themselves uniforms as the others had. On their way to the next building, they watch a broadcast on a huge screen at one of the buildings. All Nazi-style, Nazi emblems, Nazi–like speeches and behavior patterns, frightening, forcing patterns on people and controlling everyone.

They learn that the alien vessel has been hit and totally destroyed. Gladly Kirk remarks to Spock that he looks pretty healthy for a dead man. In the end Kirk recognizes John Gill as the man behind it. Gill had been a former teacher of Kirk's at the Starfleet Academy. First they hear a soldier approaching, hide, knock him down and Spock has got his uniform. Next Spock presents his prisoner to an officer and Kirk gets his Nazi-uniform, which, as Spock notices, suits Kirk well... what in turn earns him a suspicious look. Just before both enter the main building they are addressed by a higher officer who missed the Nazi – greeting with Spock.. Spock gives a hint of a wave and they try to go on, but the officer isn't happy with Spock's greenish color of skin, and, thinking that Spock somehow looks different, he wants to see his papers. Spock's astonished look make Kirk remind him that they are in his pocket of the uniform and Spock hands them over, while Kirk tries to explain that his friend is not quite himself today because he's done a lot of arrests and must be tired. The officer is not convinced and orders Spock to remove his helmet. Surrounded by many soldiers Spock has no choice. Now the officer is sure: Spock's different.

In the arrest cells they are whipped. Spock's green blood adds to the notion that he is not from here. The two trained officers together give a clear picture that they are not the Zeonists they usually encounter as "enemies", but do not give away any information. The man in charge seems to be Melakon, the highest ranked man just under Gill. One of the other high ranked officers orders the torture to be interrupted and both are back into their cell. In the cell they arrange for a jailbreak (Kirk does not enjoy Spock standing on his wounded shoulders in order to make use of a lightbulb) much to the amazement of the man in the adjoining cell and later make contact with the underground Zeonists. Here both are put to a test. Meeting the high ranked officer again they are tempted to work side by side with the Nazis. Kirk and Spock don't. Having passed the test, the present Nazi officers turn out to be part of the underground movement. Kirk gets information about his former teacher: John Gill is used and drugged by Melakon, who wants to be in power himself.

Soon a speech by Gill is planned to be broadcasted to call for war with the neighboring planet Zeon. With the help of the underground movement Kirk and Spock get to the enclosed room where Gill is kept. Realizing that Gill is not himself and might be in need of medical care, Kirk orders Spock to summon Dr. McCoy. Spock complains that the comunicator signal is feable, because of the planet shielding and states that it will hardly work, maybe it will not work at all. Kirk comments "You're always such an optimist, Mr. Spock!" Somehow, the comuication is established and they wait for McCoy, who's delayed by a ... footwear problem. When he finally beams down, the doctor is still fighting with a boot and complaining about the stupid computer that wasn't able to get him the right size. Spock icily comments: "There is a logical solution to that, Doctor. Just hold it with both your hands and push!"

Suddenly they are caught by Melakon and his guards, but Kirk orders Spock to take out his helmet and pretends to have just arrested him. While Spock is led away by the guards, Kirk and McCoy enter Gill's room, wake him up and Kirk manages in the last moments to make him aware of what has become out of his endeavors to introduce a "highly efficient" form of state-structure to the people – forgetting on which costs the power striving Nazi regime was built. Gill learns that Melakon has misused his intentions for his own interests in power. As Melakon realizes that Gill denounces any plans of war, but befriends the Zeonists and openly declares Melakon's misuse of his trust, he grabs a gun and shoots Gill while he is speaking. The speech has turned the Ekotians against Melakon and opened a way out of their self-built misery for them.