The colonization ship was entirely automated - the 500 colonists on board were just fertilized eggs. Once the ship landed the eggs were then grown in vats and were to remain in the vats for 30 years learning their particular vocation. But on this voyage the colonists were released after only 15 years due to a malfunction. And then things continued to get worse for these teenagers as they struggled to survive.
The story is told from the point of view of the colony's would-be psychologist. As usual, Howey's writing is excellent, making for a better-than-average tale of extraterrestrial colonization of a new and unexplored world.