Alpha One

 was a human colony planet. When the colonists first arrived, Walter Cantrell acquired more land than the other colonists, not always by legal means. The colonists, who feared Cantrell, began keeping to themselves.

At Christmas, a blizzard forced the colonists to take shelter in the town. The Fifth Doctor, Peri Brown and Erimem arrived to help the colonists. Erimem convinced them to stand up to Cantrell, and the Doctor suggested they get together often enough to develop a sense of community.

The Doctor later told Peri and Erimem that, in the future, Alpha One would be a focal point during a galactic war, and it was important that the right people be running the colony when the war came. (PROSE: Far Away in a Manger)