Amazing sci-fi about the planet January where a human spaceship arrived generations ago. Tidal locked, one side of the planet is always blazing, one in eternal dark.
Various people, Mouth, and Sophie, struggling between the two cities (Xiophant, strict rules, strict times) and Argelo (party, freedom, no responsibility) and the Citizens (Mouth is the only survivor) as well as the Resourceful Couriers, "crocodiles" or Gelet that Sophie can speak with...
Amazing stuff.