A warlock prepares to conquer Northland with dark magic and an army of goblins. His agents sow discontent and chaos among the people, and he summons a demon to murder the old wizard Nicodemus. Meanwhile, Sigurd, a talented young man, is on his way to the town of Northeim, when he is robbed and left to die. A strange woodsman finds and saves him, and offers him work in Nicodemus's tower.
Baron Erik Half-Moon suspects that something foul is afoot in the Northern wilderness, and makes his own war preparations. His first move is to get rid of Thomas, an influential merchant and suspected spy. It falls on Heidi, a young thief's apprentice, to gather information about the cunning merchant. But her break-in doesn't go as planned, and suddenly she finds herself in serious trouble.