Alterations to Magic

The land of Barovia resides in its own demiplane, isolated from all other planes, including the Material Plane. No spell—not even wish—allows one to escape from Strahd’s domain. Astral projection, teleport, plane shift, and similar spells cast for the purpose of leaving Barovia simply fail, as do effects that banish a creature to another plane of existence. These restrictions apply to magic items and artifacts that have properties that transport or banish creatures to other planes. Magic that allows transit to the Border Ethereal, such as the etherealness spell and the Etherealness feature of incorporeal undead, is the exception to this rule. A creature that enters the Border Ethereal from Strahd’s domain is pulled back into Barovia upon leaving that plane.
  For the purpose of spells whose effects change across or are blocked by planar boundaries (such as sending), Strahd’s domain is considered its own plane. Magic that summons creatures or objects from other planes functions normally in Barovia, as does magic that involves an extradimensional space. Any spells cast within such an extradimensional space (such as that created by Mordenkainen’s magnificent mansion) are subject to the same restrictions as magic cast in Barovia.
  While in Barovia, characters who receive spells from deities or otherworldly patrons continue to do so. In addition, spells that allow contact with beings from other planes function normally—with one proviso: Strahd can sense when someone in his domain is casting such a spell and can choose to make himself the spell’s recipient, so that he becomes the one who is contacted.
Type
Metaphysical, Supernatural