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Expedition to Undermountain (3.5)


Expedition to Undermountainis a 224-page super-adventure that revisits the greatest dungeon in the Forgotten Realms campaign setting. Located beneath the city of Waterdeep, Undermountain has lured countless heroes to their doom.

Like other adventures in the “Expedition” series, this product takes a classic D&D location, updates it for v.3.5, and features many new surprises. It also includes source material for the players and a new combat encounter format designed to make the Dungeon Master’s job easier, as well as information to help Dungeon Masters adapt the adventure to serve their home campaigns.

Product History

Expedition to Undermountain (2007), by Eric L. Boyd, Ed Greenwood, Christopher Lindsay, and Sean K. Reynolds, is as much source book as it is campaign adventure. Reworking the massive, sprawling dungeon crawl for 3.5 D&D, the campaign is designed to bring heroes from 1st level to 10th. The underground adventure location is huge, with nine main levels and about 20 sub-levels that connect to caverns, more dungeons, and the Underdark.

This book is designed to let a DM turn Undermountain into a longterm campaign setting, so it provides lore, plot hooks, and details about the power groups who clash for control of Undermountain. This is a more freeform, less directed approach than the 2e AD&D mega-dungeon version of Undermountain, but which works regardless.

All Things Pass.The world has changed, the mad Archmage Halaster has died (pretty definitively, according to the DM text - although let's face it, if you haven't seen the body, then it's still suspect). Once more, adventurous PCs enter the Yawning Portal to see what lies beneath. There is no central and over-riding quest that sends PCs into the dungeons; instead, a number of individual missions to find and recover objects lead to clashes and conflict with the various groups who hope to rule the shadowy passages of Undermountain.

The adventure begins with a strong synopsis of Undermountain, giving DMs a solid understanding of how different levels fit together and interact. Halaster's death has the opportunity to open up a power vacuum in Undermountain, and the various factions may choose to exploit that. Note that the Encounter structure, breaking out encounters into their own pages later in the book, has caught some readers off guard: It makes reading the book a bit choppy, with more page-flipping required between encounters and the map sections than some DMs are used to, even while running the actual encounter becomes easier since all the needed information is summarized on one or two pages.

Battles tend to be tactical and relatively deadly for incautious players. That's fun for many groups, but players who aren't used to working as a team may find themselves badly savaged by swarms of tiny beholder eyeballs. 

Also? There are stats for a swarm of beholder eyeballs. Consider yourself warned.

You Can't Get There If You Don't Have a Map. Expedition to Undermountain gives a side-view cutaway map of the complex, something that has been conspicuously missing in previous Undermountain products. Cartography-wise, there are a few locations developed in Expedition to Undermountain that don't easily fit into the maps of older products. The town of Spiderhaven is one of these, as is Belkram's Fall. There's also a reasonable argument that the maps of several areas are smaller than they should be, making it a bit difficult to track PC progress through the underground settlements. That actually turns into a positive, though, when it comes time for a DM to fill out and customize undescribed areas of Undermountain, for there is plenty of space and plenty of latitude for expansion.

Where's the Earth-Shattering Kaboom? Due to the nature of the beast, the DM has extensive freedom to customize his adventures within the framework that this book provides. The downside of that is that there isn't necessarily a noteworthy cinematic climax to the adventure as written. PCs have so many options on where to go and how to explore that providing a single scripted ending would be difficult. Yet even with lots of fun, exciting smaller encounters detailed within each area, DMs may want to think forward to crafting this sort of emotional and deadly conclusion to their PCs' adventures. With the tools and framework provided, they'll have a lot of options for doing so.

If you're looking at a massive dungeon crawl for 3.x D&D, or if you want superb inspiration for assembling a mega-dungeon of your own, you'll find this book both useful and entertaining.

About the Creators. Eric L. Boyd has written dozens of articles and books for Greyhawk and the Forgotten Realms, as well as for Paizo's Pathfinder.

Ed Greenwood is a Canadian writer, designer, and storyteller who created the Forgotten Realms.

Christopher Lindsay is a Washington-based designer and author.

Sean K Reynolds started as TSR's online coordinator in 1995, and has gone on to be a celebrated designer on dozens of superb products for TSR, Wizards of the Coast, and Paizo Publishing.

About the Product Historian

History and commentary of this product was written by Kevin Kulp, game designer and admin of the independent D&D fansite ENWorld. Please feel free to mail corrections, comments, and additions to

We (Wizards) recognize that some of the legacy content available on this website does not reflect the values of the Dungeons & Dragons franchise today. Some older content may reflect ethnic, racial, and gender prejudice that were commonplace in American society at that time. These depictions were wrong then and are wrong today. This content is presented as it was originally created, because to do otherwise would be the same as claiming these prejudices never existed. Dungeons & Dragons teaches that diversity is a strength, and we strive to make our D&D products as welcoming and inclusive as possible. This part of our work will never end.

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Reviews (1)
Discussions (3)
Customer avatar
Dwayne H April 18, 2020 11:28 pm UTC
Does this module come with map locations already designed so i can use them as a reference and not have to make my own maps?
Customer avatar
Roman T March 25, 2019 12:55 am UTC
is the hardcover of this identical to the original hardcover release?
Customer avatar
Cody B January 15, 2019 8:33 pm UTC
Still waiting for Expedition to the Ruins of Greyhawk in POD form, please!
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File Last Updated:
September 19, 2013
This title was added to our catalog on April 23, 2013.