Gods of the Forbidden North (POD, Black & White)

This is a print on demand copy and is not an original copy.

Gods of the Forbidden North is a massive, three-volume mega-adventure series written for the Old-School Essentials: Advanced Fantasy tabletop role-playing game by Necrotic Gnome. It details a campaign setting, a wilderness hex-crawl, a sprawling underworld connecting to multiple entrances on the surface, and most importantly, an enormous megadungeon.

Volume 1: The first book covers the arctic frontier's settlements, cultures, religions, and its vast wilderness regions. It includes an urban starter quest and five low-level dungeons.
Volume 2: The second book details the underworld below the continent's surface and six mid-level dungeons.
Volume 3: The third book explores Castle Thar-Gannon, its upper halls, mysterious towers, and underground levels. It also includes the Cyclopean City deep under the earth, which leads to the entire adventure's climax: the Tesseract of Time.
The first volume is designed for a heroic party of 6-8 adventurers to begin at 1st level and reach a minimum of 5th level by the book's conclusion, although most parties will hit 7th-8th level if all wilderness encounters are exhausted. Though the mega-adventure was originally designed as a sandbox, it also supports episodic "adventure path" playstyles, as well.