How a mediocre episode of Star Trek might be improved:
Bele is taken to Lokai, and the two begin to argue about the history of their two distinct peoples. Kirk is puzzled by the animosity between the two, who appear to him to be of the same race.
When Bele explains that Lokai is evil because his people are black on the left and white on the right, Lokai interjects that the opposite is true: Bele’s people are evil because they are black on the right and white on the left.
Kirk, in an attempt to be clever, responds that he’s white on the top and black on the bottom – which, given he is clothed, they have to take his word on. “What does that make me?”
The two Cheronians howl in instinctive horror, Kirk’s snarky question having triggered the racial memory of another Cheronian people exterminated many millennia earlier. The two aliens immediately put aside their differences and unite in a campaign of annihilation against humanity, who they now perceive as either white-top-black-bottom (Kirk) or black-top-white-bottom (Uhura) members of the feared and loathed third Cheronians.
After a decade-long campaign of genocide across the Federation, Kirk is brought before War Admirals Bele and Lokai in the ruins of Starbase 1, the final survivor of the human race. When the tatters of his uniform reveal that humans are not, in fact, different colors top and bottom, the Cheronians belatedly realize that they’ve made a terrible mistake.
“Um. So sorry about that.”
“Yes, yes. We really should have checked.”
Kirk, spared execution at the last moment, sighs with relief tinged with grief and regret. Looking out a nearby viewport at the scorched and ruined Earth passing below, he says wistfully, “If only I’d joked that we were colored front-to-back, instead.”
At which the two Cheronians scream in uncontrollable terror at the racial memory of a fourth, much older and more fearsome Cheronian people, and transport themselves into the blessed escape of the void.
Spock arrives to rescue Kirk as the wreckage of the station begins to enter Earth’s upper atmosphere. A trite moral lesson is presented, and the credits roll. In the following episode, everything is back to normal and none of these events is acknowledged to have happened.