From the publisher's website:
Beyond Countless Doorways discusses what happens when planes go into and come out of conjunction as they metaphysically move in higher-dimensional space. It also mentions the idea of a true conjunction, where two planes align so closely that they almost fuse into one single plane, at least for a time. (See my recent Design Diary for more on conjunctions.)
This web enhancement describes what might happen if a world were to come into true conjunction with an energy plane called Karlectash. Use it to introduce your players to the concept of conjunctions the hard way: having Karlectash fuse with your standard campaign world.
This five-page article details an event you can use with the Beyond Countless Doorways book of planes by Monte Cook, Wolfgang Baur, Colin McComb, and Ray Vallese. However, you don’t need the book to take advantage of this material, including the new monster: the karlectar. This free web enhancement gives you all the information you need to insert it in any d20 System fantasy campaign.