A primitive planet where the Klingons secretly arm one faction, leading Kirk to arm the other in A Private Little War.
Neural is a pre-industrial planet that Kirk surveyed as a young officer thirteen years before A Private Little War, befriending a hill tribesman named Tyree. At that time, the planet's hill people and villagers lived in peace.
When Kirk returns, he finds that the villagers have flintlock rifles supplied by the Klingons and are attacking the hill people. Kirk decides to supply Tyree's people with matching weapons in order to keep a balance of power, a choice he finds deeply troubling. The planet is also home to the mugato, whose bite nearly kills Kirk.