Shadowdale - The Avatar Series

In this landmark Forgotten Realms novel, a band of heroes seeks the one ally who can help them win a deadly race against the gods: Elminster
 
When the gods are banished from the heavens, they must travel through Faerûn in the guise of mortals, seeking to regain their powers. Malevolent Bane, power-hungry Mystra, and Helm—guardian of the heavens—all know the lost Tablets of Fate are key.

When four companions, the last survivors of the Company of the Lynx, find themselves in possession of a mysterious amulet, they must escape death at the hand of Bane, god of murder.
 
But time is running out for the heroes and the Realms. Caught in the crossfire, nature itself revolts: strange, deadly creatures stalk the land, and even magic becomes unpredictable. Now embroiled in a high-level power struggle with the fallen deities, the heroes must find the sage Elminster—the only mortal who may know the secret of the tablets. And the search begins in Shadowdale.