From the introduction:
The Lich Theleb has revived the cult to the Elder Elemental God. After successfully bringing the Earth temple back, he ventured forth into the world to find the other temples that have fallen silent over the centuries. In a remote range of mountains he has found the temple dedicated to the Element of Air. In this temple he has restored the source of power that created a rift to the Demi-plane where the Elder is trapped. This rift in the planes has caused a wild surge to all Elemental Air magic, both mage and clerical. The rift takes all Elemental Air magic cast on the Prime Material Plane and focuses it into a great storm that rages over the temple. The storm becomes stronger as more Elemental magic is incorporated into it. This storm focuses the power to the rift and sends the magic to the Demi-plane where it gives or takes power from the Elder Elemental God depending on the wild surge.
User summary:
For 9th - 12th level characters.