Lithia is a planet which humans have tried to terraform but have failed; it is now reverting to its original state. What's left of the colonists live now in 'claves' (enclaves) who are slowly drifting towards primitivism and are consumed by illnesses; only a small number have remained on the former space station, not losing the scientific knowledge. A spaceship is coming to Lithia, interested in reterraforming it, only the colonists still on the space station only want to escape the planet and thus devise a plan to geologically 'attack' Lithia so the ship will not stay. Add to this a strange decadent alien race, the orthong, who have also chosen Lithia as their home.
The book follows the treks of several characters.
First, a young man, Reeve Calder, together with a middle-aged woman named Marie, leave the space station in order to try to stop the plan to destroy Lithia. On the way, they meet a courageous claver named Spar with a no-nonsense attitude who is accompanying a strange girl named Loon. This girl seems to be adapting to Lithia in ways nobody understands and may hold the key to the survival of humanity.
Second, we see the team that plans to destroy the planet at work, through the eyes of a young boy who doesn't quite know what's happening around him. (This is the least interesting part of the book.)
And third, we follow a claver woman named Nerys who seeks the help of the orthong in order to survive. This story did not start quite so engaging, but looking back on it I think it was the most interesting of all. She slowly learns to communicate with the orthong (a very secretive race who think humans are a lower species) and even struggingly becomes friends with one of them, rising from her position as a child-bearer to that of a quasi-adviser.
There are not so many original ideas in this book, certainly nothing that would come as a breakthrough; but still, the story is told nicely, with a good rhythm, and is well put together. I followed the adventures of all characters with much interest; I cannot say I was unable to put down the book, though.
What I enjoyed most were the characters. They are all very distinct and complex personalities, and you can sympathize with each of them, understand what motivates and drives them. There is not one unjustified action or thought on their part, even when the decisions they make are not always for the best. They are all very human...
This book was pretty different in style from 'The Seeds Of Time'. That book had great SF ideas, but the writing style and the characters were not so good. This is the writing of an author who has evolved and is more sure about herself. I will certainly continue to read her books.