From the introduction:
Welcome to The Drow War, Book Two: The Dying of the Light!
This is a linked series of three 256-page books. Each one contains a single epic story broken into ten parts, thus making thirty discrete adventures in total, all tied in to one overarching saga.
The adventures are structured to take the characters concerned from 1st level to 30th level. Each book covers a span of ten levels, meaning that every adventure will (if completed successfully) advance the characters by approximately one level of experience. Naturally, this outcome is not guaranteed, nor is the progress going to be one long grind!
The story of the Drow War continues where it left off, in the aftermath of the war for Caldraza. A mysterious messenger brings the news that the threat of the drow is by no means wiped out. A strike from below will come any day now. Powerful friends wait to aid the Player Characters in the city of Crom Calamar, the unconquered capital of Jehannum, Nation of Warriors.