From publisher blurb:
A Shadow Has Fallen over Faerun
As malign forces conspire to undo the Weave and replace it with the Shadow Weave, the Great Desert of Anauroch begins to change. Unless something is done, all of Faerun will soon feel the dark might of the greatest magical empire since Netheril.
This adventure is the climax of a three-part series set in the Forgotten Realms campaign setting. It can also be played as a stand-alone adventure. In addition to encounters, this book contains detailed source material on the realm of Anauroch, home of ancient Netherese ruins and the Empire of Shade.