An envoy for the Ekumen - a coalition of worlds - visits a unique planet called Gethen/Winter where the population is genderless and sexless, and finds it difficult to understand their psychology.
Karhide is a "family quarrel" of loosely-affiliated regions, though it does have a king. The language used to describe Karhide is very sensory and concrete. Orgoreyn at first seems like an organized, centralized progressive democracy but is revealed to be an authoritarian state. The language used to describe Orgoreyn tends to be immaterial, dreamlike, disconnected.
The Gethenians have no sexual characteristics, except for occasional members labeled "perverts". Once a month, Gethenians go into "Kemmer" during which they pair with a partner and each takes on the opposite sex to mate.