To be brutally honest, Keepers of the Flame is not one of my favorites in this series. Although I would give it only 3 stars in regard to the others in this series, 4 stars is the very least I can give it simply because, compared to other novels by other authors in this genre, it deserves that much consideration.
In this story, the summoning, on behalf of the townspeople of Castleton, brings twin women (Bri and Elizabeth) who are healers. One twin is a certified doctor, the other a more magical "healing hands, new age" guru. They are needed because The Dark has let loose a plague that needs to be cured or all will sicken and die. With very little imagination we know that the magical 'hands on' cure will be the most effective, but for some reason the twin with the more traditional training is accepted and respected (even though traditional methods have already been tried and failed). The metaphysical twin is pretty much dismissed as a bit of a flake, even though her methods obviously work.
To add confusion, a third exotic (Raine) has been unknowingly summoned by the Sea Masters. No one knows she even exists on Amee. Her sad story flits in and out with little warning between chapters. For six months she has been facing a strange new world, forced to work as an abused kitchen slave, physically abused and beaten, chased by bad guys, sells her body for food, and sickens when she tries to travel more than a short distance from the sea. We are left hanging with her fate in the balance. Adding her unfinished story to the twists and turns of this novel creates an unnecessary mish-mash of continuity.
Two love interests are explored with Servair Masif (the town mayor) and our old standby, Faucon Creusse (the one who is naturally attracted to all exotics, but is always disappointed). Not too difficult to figure out who will win or lose in this repetitive contest, but the romance with both men is interesting and sensual.
My biggest concern as this series progresses is that each woman summoned seems to be getting less and less mature. The twins are whining "I wanna go home, mommy and daddy will be so worried!" Marion sobs when she says the wrong things ("I'm sorry, I didn't mean it, I'm so, so sorry!"). Alexa keeps trying to wheedle chocolate and potatoes from the twins like a kid hoping for a forbidden treat.
In short, these powerful women are becoming girls, and edging towards childhood. Their men, happily, are still sturdy and reliable.
Injury and deaths of old favorites, new magical companions are introduced for the twins (a Roc for Bri, a Volaran for Elizabeth, a baby feycoocus for Raine), Amee is suffering from the attacks of The Dark and becoming unstable as a planet, magical new efforts to keep in touch with Terre are explored.
Despite my many (and probably too harsh) criticisms, this newest effort is very readable and has a tremendous amount of information needed to keep up with the overall series. I enjoyed much of it, and I consider it a Kindle keeper.