A vortex-a fount of light that has the power to turn those it chooses into astral mages-has appeared, and both the Empire and the Nebulis Sovereignty are hot on its tail, each determined to stop the other from getting their hands on it. But great care must be exercised, especially by the Imperials, as those who dare venture too close just might find the mark of a witch freshly emblazoned on their skin...