The world that Thea Harrison has created for her Elder Races series is a complex, fully realized one with many cultures and traditions having their stories told. As you go further into the series, it becomes clear that she is committed to giving each its own time in the spotlight, and I kind of love that. It makes for richer, more interesting story telling since characters that were the protagonists in earlier novels become maybe not antagonists, but definitely on an opposing side from the main characters of the current novel. I also love that she is branching out into all kinds of mythologies, and not sticking to vampire/were lore for inspiration.
Storm’s Heart is the second entry in the Elder Races series, and tells the story of Tiago, a thunderbird, who was once revered as a storm god by the ancient Egyptians and various other primitive peoples, and Niniane (aka Tricks from Dragon Bound), who has recently inherited the Dark Fae throne from her Uncle Urien. Both were part of the court of Dragos, the hero of Dragon Bound, until Niniane steps forward to claim her throne after having been in hiding for more than 200 years. Tiago realizes that Niniane is planning to return to the court of the Dark Fae by herself and insists on accompanying her. Adventures ensue, new characters are introduced, and there is a little telegraphing of plot lines, but not so much that it interferes with enjoyment of a good story with interesting characters.
That’s all I’m giving you detail-wise. It isn’t ever phrased this way, but there is some debate over the good of the one vs. the good of the many, which isn’t exactly new, but is perhaps not so common in romance novels. You can read this as complete fluff, or you can read more into it, depending on your mood and/or need at the time.