20,000 people have vanished from the Earth and all clues point to Earth’s isolationist alien trading partners on the planet Riga. Earth’s top investigator is sent to Riga to team-up with their top investigator to uncover the truth.

The central mystery here is pretty much a secondary focus of the book as it isn’t that complex, is fairly obvious who the culprit is, and the resolution just sort of peters out.

Most of the effort is the world building and sociology of how a society of beings who can control each other’s minds is built and functions. It’s very well thought out and raises some interesting moral questions around the effectiveness of legal limitations. ( )