Centuries-long wars and internal strife have weakened the once powerful four Great Houses of Rendell (Oak, Ash, Rowan, Yew). Their totem trees are about to die. And far in the north, the Great Darkness is already gathering forces to break out of the walls of the Palace of Fire and Ice and subjugate people to its will.

The weak-willed Prince Florian, the legal heir of the House of Ash, is not able to rule the state and withstand the looming danger. But in the very heart of the vast swamps, in a place called the Sinister Mire, young Yasenka grows up, gifted with magical powers and raised by a healer, the illegitimate daughter of the king, who has the right to claim the throne...