Nok Feireiner, leader of the Cruor assassins, lives on borrowed time. And if he does not kill his last mark - Lina Edenfril - his own life will be lost. The black magic of the Oath of Cruor tests his control and he has to fight with his essence in the name of saving the woman he loves. Lina is ready to do anything to help Nok remove the oath from him. And when she learns of a creature rumored to have the power needed to save Nok's life, she sets off on an expedition to the frozen north without thinking twice. But the hunt for a magical creature quickly changed poles, and now Lina and her trusted gang of killers have become the prey... and time is inexorably running out.