A solid mix of fantasy and SF. Could have been an episode of Star Trek with humanity monitoring backward settlements on remote planets without intruding. It’s not that those settlements have evolved independently from humanity. In fact, Carrig has been settled by a human spaceship crashed there. Since, this fact has been forgotten and only remains recognizable in legends.
Now, outlaws from a rogue planet disturb the balance on medieval Carrig by intervening with superior weapons to exploit the rich resources on this planet. Scouts of the Federation try to alleviate this, allying with selected locals without revealing their identity.
There are enough interesting ideas and the world building is sufficiently original to provide entertainment without any major plot holes or implausibilities. If you like Star Trek, you’ll like this one.