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Real world article
(written from a production point of view)

"Kitumba" was a projected two-part episode for the unrealized Star Trek series Star Trek: Phase II. The episode was written by John Meredyth Lucas. Jon Povill enthusiastically described the story as "a wonderful adventure inside the heart of the Klingon Empire." (Star Trek Phase II: The Lost Series, p. 3)

Plot

The USS Enterprise under Captain James T. Kirk is sent on a secret mission. Kirk is to take a Klingon warrior named Ksia to the Klingon homeworld. Ksia was once the tutor of the reclusive ceremonial ruler of the Klingon Empire, the Kitumba. But Ksia defected to the Federation in order to prevent the imminent all-out attack of the Klingons on the Federation. This attack was conceived by Malkthon, who is the Klingon Warlord, the actual political ruler of the Empire. Ksia plans to convince the adolescent Kitumba to speak out against the imminent attack as Ksia is convinced that the resulting war would destroy both the Federation and the Klingon Empire. (Star Trek: Phase II - The Making of the Lost Series)

The alternate Klingon Empire

The episode "Kitumba" would have established a Klingon Empire which differs from the canon Klingon Empire in some notable respects:

Plot elements of "Kitumba" used in TNG episodes

Fan film