A Crane Among Wolves by June Hur

In 1500s Joseon (modern day Korea), Iseul and her sister are living under a brutal tyrant, King Yeonsan. The king has murdered all those he considers political enemies, which included their parents. The King commandeers land from his people and kidnaps young girls across the country. When Iseul's sister becomes one of the kidnapped girls, Iseul embarks on a dangerous journey, determined to bring her home. She believes the key to getting her sister back is to solve a series of murders the King has offered a great reward for. Along the way though, she meets the King's brother, Daehyun, and finds herself embroiled in something bigger than just saving her sister, that has the possibility of bringing down the entire regime. 

A Crane Among Wolves is an engrossing, and sometimes horrifying, historical mystery, filled with political intrigue, family and found family, and a bit of romance. June Hur blends historical fact, with engaging characters and a story that's hard to put down, masterfully.