This was an epic adventure filled with action, Irish folklore and mythology, romance, treachery, pain and deception. Also two stubborn, broody and complex warrior brothers, and a delightfully feisty and powerful FMC who's stumbled into a different realm. 
I loved the character growth from Cliona, she starts off as fearful and filled with self-doubt, but she grows into a remarkable force that's brave, caring, but still very sarcastic and witty. 
There is a light love triangle romance, and you will likely switch between loyalties despite a heavier attention on one brother. They both are mysterious and secretive, and entertaining characters. 
It has great tension, a hunger games style deadly contest, subplots of disappearances, an obsessed villain, and meddling Gods. 
It takes a little time to get into the main plot, but when it hits its full on, and I loved those final chapters and the shocking twists. 
It's immersive, funny, intriguing and i'm excited for book 2.