Warning: Wikipedia contains spoilers
The story is set on a planet with a period of 60 Earth years at the approach of its correspondingly long winter. Two of the main characters, Wold and his daughter Rolery, are members of a tribe of the human-like beings indigenous to the planet. The third main character, Jakob Agat, is a young man in a dwindling colony of Earth humans. Although both populations were genetically engineered by the Hain from Hainish stock, they are not interfertile.
Rolery visits the Earth people's colony. Conflicts between her tribe and the colony follow, just at a time of crisis when cooperation would be most advantageous--especially to Rolery and Agat.