Descent into the Depths of the Earth is the first of three modules in the “Descent” or “Drow” series, and the fourth of 7 modules in the special campaign series generally known as the GDQ series.

First published in 1978, the adventure picks up after the end of the Giant series, with the adventurers pursuing the fleeing drow elves into a long tunnel deep under the earth. Apart from the author (Gary Gygax) and a few legible signatures on the artwork, no credits are given for this adventure.

It’s worth noting that the artwork, mostly by Dave Sutherland, is quite poor. Some pieces buck the trend and look rather special – and are likely done by Dave Trampier – but its overall quality is disappointing. I assume that Sutherland also did the maps, which are good. (I don’t normally mention artwork, but this is such a dip under the usual quality of TSR art – much of which was brilliant – that it is worth noting).

One of the fascinating things about this adventure is that a large part of it is the travel through the tunnels of the underground on the way to three set-piece encounter areas. The player’s map and DM’s map show the tunnels of the underground in one of three forms: primary, secondary, or tertiary, and example maps of how those tunnels appear are given, along with extensive random encounter tables. As the adventure instructs the DM to check for encounters once every mile (hex) of travel, with a 1 in 10 or 1 in 12 chance of an encounter occurring, it’s likely that only one or two random encounters will occur before the end of the adventure.

This is an example of something that reads very differently to how it plays. When I first saw these tables, I was enthralled by the dangerous tunnels that I saw as teeming with the effects of the ecology and societies of this underground place. However, because random encounters occur so rarely, the players in the game won’t see this.

A little diversion now into the realm of the D&D stat block. In Steading of the Hill Giant Chief, your standard stat block looked like this: “hill giants (H.P.: 40, 43)” – that is, just the hit points. Gygax was using more varied monster armaments now, and the results were not always good. Consider these two examples:

• 11-16 bugbears (H.P: 15 each) with ring mail jacks and large shields (AC 3) and each armed with heavy morning stars (+2 on damage) and 2 heavy spears.
• Each Drow merchant is male and a cleric/fighter of 4th/4th level (H.P: 18; +3 chain mail, +3 buckler, +1 for dexterity of 15 for an overall AC of -3). Each is armed with a +2 mace. They have the following spells…

and so on and forth for another 5 lines.

Detailing where each of the parts of AC comes from might be necessary, but the verbose style makes it difficult to identify exactly what their final stats are. In later adventures, the stat block would be streamlined and made more consistent. However, TSR wasn’t there yet!

The adventure relies heavily on the map, which shows long tunnels reaching a few encounter areas – of major and minor significance. The player map (one dropped by the fleeing drow at the end of Hall of the Fire Giant King) occasionally omits encounter areas, which gives an extra set of tension.

The first two keyed encounter areas detail a drow checkpoint (which must be encountered) and a mind flayer spy post (which can be avoided). Both are described as combat encounters, with little thought to negotiation. The drow checkpoint is particularly interesting for the insight it gives into the culture of the drow: there are two separate patrol groups (male and female), who are rivals with each other. We also gain more insight into the complicated politics of the drow: it seems not everyone in the drow homeland approves of Eclavdra’s plans.

However, the meat of this adventure is in the final encounter area on the map, which contains the caverns and warrens of the troglodytes. The map is big, spreading over two panels of the gatefold cover.

The adventure describes 40 encounter areas in these caverns, featuring both combat and role-playing encounters. There are drow overseers, a hidden lich, bugbears servants, packs of ghouls and ghasts, and – of course – a lot of troglodytes.

On particular note, the caverns show the drow control over the inhabitants of this underground realm. As an adventuring locale, it excels in the variety of foes and the treasures to be won, although there are a few nice Gygaxian touches throughout.

All of this takes up eleven pages. The twelfth page of the adventure describes a new monster: the Jermlaine (Jinxkins). Unusually, these one-foot-tall humanoids only appear in the random encounter tables for the least-travelled tunnels. I think that Gygax may have felt there was a need to include a new monster, but Jermlaine are not interesting nor needed as part of this adventures.

The final four pages are one-sided (so two pages of information), both perforated, one with the player’s map of the tunnels and one with DM maps for tunnel encounters. Yes, effectively they’re battle maps showing how tunnels might have obstacles or side corridors to make random combats more varied.

This isn’t the most challenging of adventures. It has an evocative theme, but the intensity of the challenges has dropped since Hall of the Fire Giant King. This is intentional, for the final two adventures would be significantly more difficult to play and to run, and a gentle introduction into the new adventuring environment was required.

One note: if the players would be so perverse as to move off their copy of the map into the unexplored reaches of the Depths, the DM did have a full map of the area and where the tunnels lead and where the major encounters areas were… but detailing of those encounter areas was up to the DM. Perhaps the most evocative of everything in this adventure is a small area on the DM’s map entitled “The Sunless Sea”, which would be referenced again in D3 Vault of the Drow.

I’m quite fond of Descent into the Depths of the Earth. It might not have the impact of the later adventures, but the concept of these extensive tunnels under the earth was exciting, and it provided the seeds for later scenarios. Not a great adventure, certainly, but a good and interesting one.

(Note: I’ve provided a link to the compilation D1-2 adventure on the DMs Guild of the adventure; the original monochrome version is not available as of this writing).