Queen Thirrin believed the bad-seed sorceress, Medea, was gone for good, but banishment did not kill her; it made her stronger. Allied with Cronus, her grandfather, Medea is raising an army of the undead to invade her family's kingdom. Her father Oskan believes he may need to summon his own black magic to stop her.

When her father dies nobly in battle, fourteen-year-old Thirrin becomes Queen of the Icemark, a tiny kingdom for ever caught between dangerous neighbours. Thirrin must raise an army to protect her people from seemingly invincible Imperial invaders. Her search for allies takes her beyond her northern borders, to former enemies in the Land-of-the-Ghosts and onwards to the frozen Hub ofthe World. But can she save her kingdom?