After an attack on the Order fortress where he was completing his apprenticeship, the apprentice finds himself as the only surviving member of the Order. He must set traps and hazards, and use his skills with bladestaff,crossbow, and magic to defend the fortress and its rifts from the horde of gruesome monsters.
As the attacks continue, the apprentice learns of an intelligence behind the horde: the Sorceress. Once a powerful member of the Order, the Sorceress entered the other world to use magic to control an army. She seeks to crush the rest of the Order, which, by the end of the game, is only the apprentice. He figures out that the rifts are what provide magic in both worlds. In the end, he seals all the rifts. While this separates the worlds, protecting the human world from the orcs, it also removes the source of magic that the human world had relied upon to make their lives better (for example, weather magic was used to dispel droughts and healing magic was used to stop disease). This leads to a weakening of the human world.