Kadrai Keep has recently been under some sort of magical 'dome' which prevents anyone from going in or out while it is up. Over the last few weeks it has been intermittant, but lately, it has been up nearly all the time. It can be seen as a nearly invisible shimmer over the Keep which just clears the tallest point.

Professor Kadrai explains that the ritual requires an accurate model of the place to be protected and at least six magical crystals spaced around the circumference. Of course, the larger the area, the more crystals are required and also the amount of magical power required is proportional to the square of the radius of the circle. The model needs to be encased in a hollow half dome crystal which defines the volume to be protected and placed in the center of the protected area.

Deep Crystal or anything else suitable for holding magic will do for the anchoring crystals and they have to be placed equidistant around the circle - the more that can be used to decrease the distance between them, the better. Kadrai Keep required twelve.

Unfortunately this method won't help Frostville because it's too big and an arcanist is required to keep the ritual running, who has to be inside the circle at all times.