Into the City of Spiders is designed as a continuation of Prisoners of the Drow wherein adventures stormed a drow outpost, confronted the drow mage in charge, and freed several captives. In this adventure, the heroes must travel through a magical portal to House Oussiryn's compound in a drow city in pursuit of the rest of the captives. There they confront drow soldiers, wizards, high priestesses, and demonic creatures.

The adventure is designed for a party of five adventurers between levels ten and thirteen. It features:

Encounters by Level - Varying types and quantities of creatures are suggested based on the party's actual level, allowing each encounter to present the appropriate challenge to the party.
Encounter Notes - Suggestions for how to run combats are provided for game masters who place an emphasis on engaging, tactical battles.
Inciting Action - Suggestions for ways to present the adventure to players are provided.
Ease of Use - The format and style of the document allows the game master to find information quickly while running the game at the table.
Detailed Maps - What's an adventure without maps? Not much else to say here.