I've recently finished the third of these. Having only read A Monster Calls previously, I had an image of Ness as a writer, and certain expectations of the books. What a versatile writer he is! Totally different from A Monster Calls; utterly wonderful.
The book is based on a series of conflicts between settlers on another planet, set in the future. The characters are wonderfully drawn, as I expected, and there are similar themes, such as teenagers struggling to take control of their own lives and destinies.
It's a great exploration of history/culture/circumstances, and how they are presented to us, and how prone we are to acceptance of the status quo.
A good place to move on for those who enjoyed The Hunger Games.