From publisher blurb:
In the center of Al-Shirkuh lies a burning wasteland of choking ash, boiling mud pools, chocking sulfur, scorching winds, and rivers of bubbling lava. In the core lies a vast crater, fed by lava rivers, its heat the enemy of flesh, its glow a beacon that illuminates the desert for countless leagues. Never conquered, it is home only to fire giants, elemental beings, and a handful of hardy orc tribes. This is the Heart of Fire, the nearest thing to the elemental realm of fire mortals can explore. It is an arid, lifeless realm that offers no pity to the weak.
Inside you’ll find:
Expanded information on the cult of Geb-Agni (god of earth and fire), including major festivals.
Information of the creation of the fiery realm, its fire giant ruler, King Surtur, and its many perils.
6 new locations to explore and two major NPCs to encounter.
3 minor deities.
5new monsters, including the fearsome lava dragon and choking soulfur cloud.