Six Crimson Cranes Tome 1

Princess Shiori'anma has a secret : forbidden magic runs in her veins. Until she loses control on the morning of her unwanted betrothal, and is discovered by her stepmother, Raikama. A sorceror in her own right, Raikama banishes Shiori, transforming her brothers into cranes, and warning her that she must speak of it to no one : for with every word that escapes her lips, one of her brothers will die.
But as Shiori searches for her brothers, she uncovers a dark conspiracy to seize the throne. To save her kingdom, she must place her trust in a paper bird, a mercurial dragon, and the boy she fought so hard not to marry. And she must embrace the magic she's been taught all her life to contain - no matter what it costs.