A Three-Round Adventure for 1st - 3rd Level Characters
From the introduction:
A remnant of ages long past, it is impossible to say who originally laid down the magical mushroom barrier that stopped the encroachment of the manifest zone known as Thelanis Wall (also called the Faerie Wall by the giants). Its borders were constructed for a very specific purpose however: to stop the spread of the manifest zone within. Thelanis, the plane known as the Faerie Court, makes the area known as Thelanis Wall a strange and wonderful place, but also a danger to those who make this part of Xen’drik their home. The same magic that curtailed the manifest zone created a rift in the earth that opened up a great spring, allowing the water to pour forth from the spring. The creatures that lived near the spring, amazed and terrified at the new source of water there, built a temple to house the new spring.