The colony consisted of 150 men, women, and children who launched from Earth in 2263. The philosophy behind the colony was a return to a less complicated life. The colonists brought only a few mechanical devices (including a subspace radio that subsequently malfunctioned) and no weapons or motorized transport. The colony was divided into three settlements (the main one had 45 residents) to ensure that if disease struck one group, the others would have a chance of survival.
The colonists arrived on Omicron Ceti III in 2264. This was not the first attempt to colonize the planet; previous efforts had failed to reasons unknown, later discovered to be the presence of deadly berthold rays. These rays were unknown to science at the time the colonists arrived, but fortunately colony botanist Leila Kalomi discovered the Omicron pod plant and the Omicron spore they emitted. These spores not only protected the colonists from the berthold rays, but also gave them perfect health and peace of mind.
The colonists brought animals for breeding and food purposes, though these were killed by exposure to the berthold rays. The colonists grew grains, potatoes, and beans in the rich soil of the planet, though only just enough to feed themselves.
On stardate 3417.3 in 2267, the USS Enterprise came to the Omicron colony to ascertain its fate given the recent discovery of berthold rays. The colonists infected most of the ship's crew with the spores, causing everyone to mutiny and beam down to the planet's surface. Only Enterprise commanding officer James T. Kirk was unaffected; he discovered that strong emotions destroyed the spores and used that knowledge to free Commander Spock from their influence as well. The two of them were able to build a subsonic transmitter capable of destroying the spores in everyone's system, "liberating" the entire colony.
The colony, once again under threat from the berthold rays, was evacuated to Starbase 27. Sandoval expressed regret that he and his fellow colonists had spent three years accomplishing nothing, and planned to start over again on a new planet. (TOS: "This Side of Paradise")