A1: Slave Pits of the Undercity is the first in the classic "A" series or "Slaver" of adventure modules published for use with the 1st edition D&D game. It was originally used as a "tournament" module, and even the expanded version of the adventure displays the effects of this. The module provides two versions of an adventure - the first is a channeled, simple version for use in "tournament" play including the official scoring system. The second is a more expanded version for use in "regular" play.

(For those who do not know, many of the early TSR D&D adventures were originally designed to be used at Gaming Convention RPG tournaments. Players would play through a portion of the adventure, be scored by how successful they were, and those who did well in the first segment would play in the next until the "best" players were selected. Most modules were two rounds long, but some were three or more).

The back story of the adventure is very basic: raiders have been abducting people to be sold as slaves and the heroes have tracked them to a ruined temple in a villainous city. The tournament version has characters starting at a secret entrance and guided through a series of encounters thereafter. The non-tournament version gives the characters several options to enter the complex, some of which are wiser choices than others. The upper level of the adventure is somewhat oddly laid out, as it is divided into two sections with no internal way to get from one to the other - an odd architecture to say the least. Some of the encounters seem oddly designed too, as the villains are found behind traps or in inaccessible areas where one would assume they would have starved or died of boredom before the PCs showed up.

If the PCs muddle their way through the upper level, they find themselves underneath the temple on the "sewer" level, in the titular Undercity. Once again, tournament characters find themselves channeled along a predetermined path of encounters, while those using the expanded version of the adventure will find a variety of choices present themselves. The sewer level has the usual assortment of orcs and ogres, but also introduces the aspis, an ant-like race that, as far as I know, was never used in a TSR adventure again (not even subsequent adventures in the "A" series). The motivations of the ant men are not explained, why they have taken up with the slavers is something of a mystery. The adventure has some interesting encounters, including a fight over the "slave pits" and a pretty satisfying final encounter, but some of the non-tournament material seems like the author just threw a big pile of monsters in a room.

The adventure includes "tournament" characters for players to use when tackling the module if they want to replicate the tournament experience (or just want to use them) and, as was pretty typical of many adventures of the era, the statistics for a couple new monsters - the aforementioned aspis, and the somewhat underwhelming giant sundew. The adventure is now regarded as a classic by many, and it has many good points. There are a couple odd quirks that were glossed over when it was published, although nothing a halfway decent DM could not patch up with only a minimal amount of effort. ( )