The United Earth Colonisation Team was made up of the flight crew of the colony starship Erehwon. Their mission was to terraform a planet in order to make it suitable for human life following the mass evacuation of Earth's human population at some point in the far future. (TV: Smile)
The colonisation team was made up of dozens of members of the flight crew that populated the starship Erehwon. Goodthing, Kezzia, their mother, Hopeful, Sunshine and Eliza were some of the team's members. (TV: Smile)
At some point in the far future, the Earth was devastated by some unspecified conflict or disaster, forcing the mass evacuation of the surviving human population on starships such as the Erehwon. After a lengthy journey through space, the ship landed on the extrasolar planet Gliese 581 D. The onboard computer then awakened a number of the flight crew from stasis with the purpose of terraforming the planet into a perfect human colony.
The team deployed swarms of Vardies, microbots that successfully terraformed the planet's surface and then built a city that would serve as the colonists' home. However, the Vardies were programmed to maintain happiness. When Goodthing and Kezzia's mother died of natural causes, her friends and family began to grieve. This caused the Vardies to identify grief as the enemy of happiness and they swiftly killed anyone who was displaying it. In just one morning, the entire set-up team was wiped out.
A short while later, the Twelfth Doctor and Bill Potts visited Gleise and discovered what was happening. The Doctor resolved the situation and made coexistence between the Vardies and the humans possible, thus ensuring the survival of the human race. (TV: Smile)