I get the distinct impression that Morgan Rhodes wanted to write a sort of young-adult version of "A Song of Ice And Fire" -- violence, frequent death, political clashes, and some (discreetly non-explicit) sexual themes. 
 And in that way, "Falling Kingdoms" is a decent debut for this author. It has a very well-plotted concept that promises to make an intriguing high fantasy series, but it also suffers from a lot of flaws that budding writers are often plagued with. It's a decent debut, but Rhodes needs some more polishing for the story to become excellent. 
 There are three kingdoms -- wealthy Auranos, impoverished and superstitious Paelsia, and brutal Limeros. When a drunken Auranian nobleman kills a Paelsian boy in front of Princess Cleo, it inadvertantly sparks off an excuse for war, causing Paelsia and Limeros to form an alliance to take down the country they hate and envy. 
 Cleo is struggling with her own problems: an engagement to a blackmailing cad, her growing love for a guard, and the illness that is slowly killing her sister. But her attempts to chase down a legend take her into the heart of the blossoming war, and bring her face-to-face with Jonas -- the brother of the man her fiance killed. 
 In Limeros, Prince Magnus' forbidden love for his sister Lucia takes an unexpected twist when he finds out that she is the subject of a prophecy -- a legendary sorceress who may become the Avatar... sorry, bring together all the elemental magics (earth, air, fire and water) and restore magic to the world. And the cruel King Gaius intends to use her to bring down Auranos. 
 The verdict? It's... okay. 
 Rhodes spends a lot of time sketching out the different cultures, back-history and mythology, and deftly weaving them together. There are a different layers to the conflict -- aside from the mere clash of kingdoms, there are also personal hatreds and even a mystical, religious dimension to the conflict. 
 And for fans of more mature storytelling, there is a lot of blood, death and implied sex (though nothing explicit, just mentions of it). The whole thing explodes in the final third, where Rhodes rushes us through the ugliness of a battlefield -- lots of disembowelments and stabbings. 
 However... Rhodes is a first-time writer, and it shows. Her prose is strong and muscular, but it has some rough patches -- repetition (take a drink every time Cleo is threatened and/or captured) and too much TELLING instead of SHOWING. 
 And it could use a bit more embellishment. One scene has Cleo having a nightmare about being drowned in blood by the murdered boy... but you don't FEEL the fear and horror of it. It needed more atmosphere and detail. 
 But Rhodes gives a lot of care to her expansive cast -- a rebellious princess who manages to avert the usual tropes, a tormented young man hardening into an ice prince, a fiery revolutionary, and even a Watcher who... just watches. Lucia is a bit of a purity Sue, but she isn't too bad as a "chosen one" character. And there is a vast supporting cast of kings, guards, peasants, barbarian chieftains, kindly old ladies and scheming witches. A lot of people die, and not always the ones you expect. 
 "Falling Kingdoms" has the skeleton of a great epic fantasy, but Morgan Rhodes needs to smooth out some of the rough spots before it can fully blossom. But this is something to keep your eye on.