The Umae live on planet Uma, and so do the more primitive Hek. Following a traumatic episode in their history, the Umae have deliberately isolated their small settlements from the Hek and each other, kept their population static, and abandoned technological progress. Which seems rather silly if they want to survive, but presumably there are reasons. Anyhow, while the Umae settlements maintain a simple, tech-free lifestyle, living under strict laws (the Protocols), their spaceships search for a safe new planet they can all move to. The space travellers hibernate through their journeys, returning to their homes generations after they set out.
The spaceship Starshine returns after one such voyage to find there are problems at home. Another spaceship has preceded them, but its crew are mysteriously missing. The Hek aren’t behaving as expected. And the people running the settlement may be up to no good.
The writing is readable with few editing errors. The main annoyance is the use of coined words, such as ‘rotation’ instead of day, and ‘ellipse’ is presumably a year. Despite that, and rather thin characters, there is plenty to enjoy here. The plot bounces between two main threads, there are body-stealing aliens, the possibility of discovering the new home planet, political skullduggery, and the mysterious past.
Unfortunately, this is very much a part 1. It ends with all the plot threads hanging, and nothing is resolved.