Caelarus was a very interesting and sometimes romantic story. I would say that the level of plausability is very high. It is 190 pages; a full book, not what some people who sell e books call them. I think the writing was very good in spite of the fact that I sometimes struggled to see who was talking.
There are lots of different settings and several Sci Fi theories that bear some thought.
Reading such work, I realize that it has been years and years since I read Asimove's "Foundation Trillogy". Now I hear there are six of them. I best get to that before my Cataracts preclude such things.
I fear for the people of Caelarus; such a peaceful and loving race.
At $6.50 it was a bargain.
Much peace
Gwendolyn