Synopsis (From Goodreads):
From the author of the New York Times bestselling Testing trilogy comes a sweeping new fantasy series, perfect for fans of Victoria Aveyard and Sarah J. Maas.
Twins Carys and Andreus were never destined to rule Eden. With their older brother next in line to inherit the throne, the future of the kingdom was secure.
But appearances—and rivals—can be deceiving. When Eden’s king and crown prince are killed by assassins, Eden desperately needs a monarch, but the line of succession is no longer clear. With a ruling council scheming to gain power, Carys and Andreus are faced with only one option—to take part in a Trial of Succession that will determine which one of them is worthy of ruling the kingdom.
As sister and brother, Carys and Andreus have always kept each other safe—from their secrets, from the court, and from the monsters lurking in the mountains beyond the kingdom’s wall. But the Trial of Succession will test the bonds of trust and family.

With their country and their hearts divided, Carys and Andreus will discover exactly what each will do to win the crown. How long before suspicion takes hold and the thirst for power leads to the ultimate betrayal?

Plot:
Relying on wind power for energy, the wind powers the light, which are used to keep the monsters away from the kingdom of Eden. With the cruel King Ulron, Queen Beatrice they had a son, the heir, Micah, and twins: Carys and Andreus. Ulron had the final say, yet ruled his kingdom by the guidance of the council and a seerer. People believe the seerer to predict the future of Eden, such like which way the wind would blow. When a seerer is considered no longer trustworthy, they are killed and replaced. When Andres and Carys were born, the current seerer told the Queen that one of her children would be born cursed. Believing it to be Andres with his weak heart and lungs, Beatrice sets Carys on the path to do one thing with her life: protect her brother. Carys take this job personally, taking beatings for her brother, to protect him, as she told him this “We are a team. I promise to protect you as I always have” (91). The current seerer, Imogen, showed up claiming this is where she is to find her new family (after losing her last one) and did after saying yes to Micah’s hand in marriage. But Micah did not love her; he was only marrying her for the power her sight provided. But Andres fell head over heels for Imogen and secretly hated his brother for stealing her away from him. When Ulron and Micah take their guards to check on the front lines, only five came back. The king and the heir were dead. Refusing the throne, the council wanted to start a new line when Imogen found a rule saying that if there are two contenders for the throne, they are to fight for the throne, one winning the crown, the other receiving death. The trials were top test the seven virtues that Eden value upon: Humility, Strength, Patience, Chastity, Temperance, Charity and Endurance. Fighting to keep their line of royalty alive, they divide the kingdom colors of blue and yellow to show support, yellow for Carys and blue for Andreus, and pin the twins against each other. Carys never lose faith, promise to keep her brother’s secret and find a way to get him on the throne while keeping herself alive. Having everything Andres wanted almost in reach: the throne, Imogen, the love of his people, Andres was willing to do anything to make his dreams come true, even killing his sister.

Thoughts:
Joelle Charbonneau wrapped you into this tale of royalty taking from the point of view of Princess Carys and Prince Andreus. You have got a sense of their personality straight off: Carys willing to do anything for her brother, anything meaning from public defiance of their father, to keeping her friend count down to one (Larkin).  Andreus, you started off liking, smart and knowledge, where he was never meant to rule, he was happy learning from the Masters and keeping the city alight at night. Yet when Charbonneau added the twist killing of the king and heir, making the twins chances at the throne a real thing. Character wise, they both dream of the throne, as the closest next in line who would not, but never gave it much thought before now. The real strength of character shown when Carys were beaten for distracting the guards from Andres (so that he could sneak away and have his panic attack in peace) and afterwards, when returning to her room (where Andres usual comforts her for taking the hits for him) found it empty because Andres would rather sleep with Imogen, who is now free from Micah. Keeping their love  a secret, because the people would think she is only doing this to be Queen (which is true because why would people believe that the fiancée to the heir, a few hours after his body has been brought back was found in bed with the next heir because she actually loved him all this time? Yeah, not happening), she promised Andres that they will work together to defeat Carys. Tossing Carys aside Andres believes Imogen (the love of his life), and takes her word as truth to everything she said about Carys and her actions. Carys who spend her entire seventeen years protecting Andres, evening plans on giving him the throne, feels the backlash of his misbelief. Truly shocking for the readers as you wanted to see the battle twins beat the system, instead you get the I-Will-Do-Anything-To-Win-Even-Killing-My-Twin brother, and the I-Just-Want-Us-To-All-Get-Along sister, who wants to protect her brother from Imogen, who might not be as honest as Andres think she is. Battle for love, family, and the crown, this book describes the first to what is going to be a great series, as the true secrets about the twin’s curse arises, more about the monsters who territories Eden, you see how far Carys is willing to go to protect her brother, and how little Andres cares for her.