Ekosians were a humanoid species from the planet Ekos. They are a pre-warp civilization.
They were in a state of anarchy. This drew the attention of the Zeons and the Federation. The Zeons came to Ekos to help the Ekosians learn peaceful ways.
The Federation sent historian John Gill as a cultural observer. Instead, he abandoned the non-interference policy and created a dictatorship-type government. The Ekosians nearly dropped a nuclear bomb on Zeon.
The U.S.S. Enterprise was sent to find out what had happened to john Gill. The crew was able to stop the deployment of the nuclear bomb. The two planets were able to come together.