Be prepared for a very long review. 
 I loved this book! The writing style has the "fairytale" tone the author uses in some of her other works: a bit mystical, a bit real. But most of all, I liked the characters. 
 There are two main plotlines in this story: 
 Blackthorn and Grim's story: 
 The main plotline and the one that stretches beyond the first book and on to the following ones. The story starts with Blackthorn, a prisoner at a horrible place, who has been looking forward to the time when she can expose her case to the council and make the chieftain pay for his evil deeds. The day before her chance, a year into her imprisonment, she is told that she'll be killed before her council meeting. A fey man by the name of Conmael offers her a deal in exchange for her freedom and she reluctantly agrees to it. The conditions are: 
 1.	She'll work as a wise woman (her profession before being held prisoner, a mix of a healer and a witch) in a country to the north, Dalriada, for seven years. 
 2.	She'll use her knowledge only for good 
 3.	She'll answer every cry for help 
 4.	Every time she fails to meet with one of the conditions stated above, a year will be added to their agreement. 
 Blackthorn hates this agreement due to her thirst for vengeance and justice, but agrees in order to gain her freedom and escape death. In her journey north, after her escape, Blackthorn notices that she is being followed by other inmate, Grim, a man in need for a purpose in life. Hearing his cry for help, Blackthorn allows him to follow her to Dalriada. 
 A can't tell you enough how much I loved both characters. They harbor darkness inside of themselves from the time of their imprisonments and the mysterious reasons why they ended up in that place. Blackthorn is full of anger, resentment and desire for vengeance to the point it blinds her, making her arrangement of waiting seven years to bring the chieftain to justice a torture. 
 Grim, on the other hand, is an enormous bear with a lot of physical strength and very straightforward thoughts. He is considered a bit of a dimwit at the beginning of the story by most of the characters, but as we get to know him we understand that his silence and little words hide a lot and that, despite his straightforward thinking, he is not an idiot at all. He thinks very little of himself, and is hunted by something horrible from his past. My favorite character by far. 
 Conmael is a mysterious character, He seems to know Blacthorn from the past and his motives for helping her remain secret. You never know his true intentions, as he is fey and they are known for playing with and tricking humans. 
 Although Backthorn and Grim are tormented souls, they complement each other in every way and make a great team to help others and themselves. There is no romance between them, at least for now, but I think that if they continue to grow and overcome their darkness, a spark may start. 
 Prince Oran and Lady Flidais' story: 
 The second plotline is straight forward and has a conclusion within the book. I believe it to be an "auxiliary" story that helps develop Blackthorn and Grim's characters while introducing new ones. 
 Prince Oran is a dreamer, a romantic, with an unconventional personality for a prince. He longs to experience a love like those of the stories (who doesn't?), but is pressured to marry and have kids by his parents in order for him to fulfill his duties as the heir to the throne of Dalriada. 
 Knowing he is 22, he starts corresponding with one of the suitors presented by her mother: the sweet and gentle Lady Flidais. He falls in love through the letters and, apparently, she does to. The wedding is set into motion, but when lady Flidais arrives she turns out to be extremely different from the letters. Everyone thinks she changed due to shock after witnessing one of her maids drowning in a mysterious pool the day of their arrival to Winterfalls, but the prince suspects that there is something more to it refusing to believe the person he fell in love with doesn't exist. 
 Blackthorn and Grim, newly arrived to Winterfalls, get mixed up in the mystery and the villagers' life, much to Blackthorn's dismay. 
 This plotline is a bit predictable and that's why I didn't give the story 5 stars. However, as I said before, I believe the second plotline is auxiliary and the main focus is the relationship between the characters and the development of Blachtorn and Grim's characters. 
 Overall: 
 Setting aside the predictability of the second plotline, I enjoyed the story very much. I admire the depth of Blackthorn and Grim as characters and is wonderful to see them fighting their inner darkness step by step. Bear in mind that before starting to read: the characters are the star of the book, not so much the plot itself.