In an icebound palace of magic and menace, a young woman plots to outwit a cruel king in a bracing fantasy about love, found family, and immeasurable revenge.

Brynja spent her childhood as a captive performer in Tenebris, the imposing mountain palace of King Kallias. Every night she risked death for the king's entertainment until his rebellious son, Prince Ballast, helped her escape. Now twenty, Brynja has never forgotten the brutal king. Or forgiven him. Under the cloak of a three-month-long Winter Dark, Brynja is returning to Tenebris for revenge.

Accompanied by a rival court, including the alluring Prince Vil, Brynja poses as diplomatic royalty to barter peace between nations. No one is better equipped to infiltrate the palace than Brynja--she remembers every hidden passage like a bad dream. But her quest to destroy Kallias is complicated by her feelings for Prince Ballast, whom she isn't sure she can still trust. And Kallias's own quest to mine a catastrophic weapon of war buried in the mountain's heart will threaten them all, and force Brynja to face the darkest parts of herself.

The lives of everyone she loves depend on the choices she must make. So, too, does the fate of the world.