Publisher's blurb:
A Descent into Avernus Side Trek
This book is designed to be used during the actual adventure of Descent into Avernus or it can be used completely independently while allowing other heroes to see to the salvation of Elturel.
The adventure begins in hell, near the infamous Pillar of Skulls where the PCs learn of Zariel's secondary plot through the lying voice of a tiny quasit demon's skull.
The adventure pits the PCs up against some interesting new creatures and other foes, though one might take a little more of an interest in the PCs than they might be comfortable with. The PCs will be introduced to the Spirit Realm, infernal landsharks, a petrified titan and the fortresses that have been made out of his corpse, two awful hags and a dragon unlike they have ever seen before.
Finally the adventure concludes in the former outpost of Baldur's Gate known as Fort Flame, which disappeared during the Spellplague and has since returned with the Sundering. Once the incursion has been thwarted, do the PCs remain in Fort Flame on the fabled continent of Anchôromé or do they return to Avernus to continue the struggle against a Lord of the Nine?