Katja is a girl born with two eye colors, blue and green and the grace of killing, or that’s what she thinks. She meet a lienid prince calling himself Po. Po have a silver and a golden eye and the grace of perception, his grace it to read thoughts about himself in a way than can make him use it in a fight. After not doing a task of killing that her uncle the king Randa of Middluns give her, she and Po leave on a journey to the kingdom of Monsea to look up if the king there, Leck, have a grace to change the truth with his words. On the way there they discover that Katja doesn’t have the grace of killing but the grace of Survival, she also falls in love with Po and Po with her.
They travel over the mountains together to Monsea and the first thing they see when they get over the mountains is Po’s aunt, the queen of Monsea, getting killed while sending signal to Po that they should find and save Bitterblue, her daughter the princess. Before they flee Po tries to kill Leck but was unsuccessful and receive wounds that made him lose his eyesight.
When they flee Monsea they leave Po in a hut in the mountains between Monsea and a kingdom named Sander, the kingdom they traveled through to get to Monsea. Katja take Bitterblue through a dangerous path through the mountains to avoid Leck’s soldiers and travel with a boat to the lineid island, to Po’s castle. There she meet Leck and while putting up resistance to his voice she throw a dagger at his head and kill him.
They go back to Monsea after that to find the hut Po was in and to make Bitterblue queen with the help of her uncle, Po’s father the lineid king and Po’s brothers. It was when Po was found that Katja realizes that he had lost his eyesight.