A system-neutral, table-driven, subterranean labyrinth full of hazards and surreal creatures.

How to use: Read through the options here and either pick ones you know you want, or (better) roll for them. Determine your boss ahead of time if you’re using one. A boss isn’t strictly necessary. Neither is an exit.

  1. Each kind of chamber will have a number of exits as indicated in the table. These are in addition to the way the PCs entered the room but can be dispersed around the chamber. Roll or pick some features for the chamber.
  2. Keep rolling new chambers as the PCs explore (but not before they choose a direction), rolling again if you come up with a boss encounter or exit.
  3. Once you’re ready, you can allow the PCs to encounter a boss or exit instead of rolling again.
  4. If the PCs reach an exit, and they’ve fulfilled the other conditions of this maze, they’ve succeeded. If they reach an exit but haven’t accomplished their goal, they simply know the way out.
  5. It can be helpful to keep track of the rooms types, exit configuration, and paths the PCs have taken in case they want to backtrack. Encourage the players to keep their own map in addition to or instead of yours.

Other tips

  1. It can be useful to determine how long you think a chamber or segment should take if no obstacles or hazards are encountered. Then you can add time from there.
  2. Scouting or any other activities PCs can use to learn what’s ahead should take time, but reduce the chance of taking a wrong turn or stumbling blindly into a hazard.
  3. PCs should usually be able to turn around and go back the way they came unless the tunnels are very unstable.
  4. You can extend the current chamber type to the next chamber as you see fit. This means, for instance, you can end up with a submerged chamber followed by a submerged dead end!

Room Encounter Types

Roll here first to determine what the room type ahead will be. Then roll the number of exits, if indicated.

d8 Subterranean Chambers Exits
1 NPC Encounter 1d4
2 Dead End 0
3 Hazard 1d4
4 Safe Place 1d4
5 Fabulous Treasure 1d4
6 Enemy Encounter 1d4
7 Boss Encounter or Adventure Site 1
8 Exit or Roll Again 1

If you like, roll for some additional room features to add flavor.

d66 10 20 30 40 50 60
1 Stalactites Stalagmites Curtains Shallow pool Running water Cave paintings
2 Fossils Collapsed rocks Chimney Columns Rimstone dam Helicites
3 Cave pearls Flowstone Gypsum flowers Epsomite snow Gypsum crust Cave popcorn
4 Soda straws Calcite raft Dogtooth spar Deep pool Sinkhole Bridge
5 Overlook Animal tunnel Tracks Old campsite Refuse Mineral deposit
6 Ore seam Preshistoric bones Ancient carvings Ruin Bioluminescent organisms Spent mine shaft

NPCs

Feel free to roll in each column to mix and match the characteristics.

d6 NPC Encounters Has Wants
1 Mine scouting party Knowledge of nearby tunnels Ore, gems, money
2 Lost traveler Little of value To know the way home
3 Smuggler Illicit goods Interesting trinkets, money
4 Undertunnel resident Alchemical reagents, interesting trinkets, knowledge of nearby tunnels Solitude, interesting rocks, mosses, mushrooms
5 Deepgoblin Merchant Interesting trinkets, overpriced tunnel gear Money, locations of treasure caches
6 Group of spies or thugs on a mission Orders, gear, weapons To leave the tunnels, to find their objective

Dead Ends

(1) The passageway here grows narrower and narrower, eventually blocking further progress forward. (3) You feel your way through the jagged contours of this chamber, but there are no openings here except the one by which you entered.
(2) A yawning chasm opens before you. You cannot sense where the bottom is, nor can you tell whether there is any passage beyond it. (4) After following a curving path that rises perceptibly, you find yourself having doubled back, and you can see the path you were on beneath you.

Roll 1d4 whenever the party encounters a dead end. Dead ends usually only cost time (and therefore time-based resources), but can occasionally harbor enemies, NPCs, or other features. Feel free to roll again to see what else is here.

Hazards