Sewer Exploration in Cy_Borg

The conceptual connection between sewers and dungeons in a cyberpunk setting is obvious, but what happens when the GM wants to use them as a journey rather than the destination?

I’ve been planning an upcoming session, where narratively, it makes sense that the PCs would sneak through the sewers to avoid detection from a security presence. Most GMs have experience building a dungeon underground, but I quickly realized that a dungeon would be way too slow when the real goal is getting to the place they want to be. The sewers themselves are really just a hindrance to that, a challenge put in front of them that is rewarded by getting there quicker and undetected. So running an encounter like this should be as swift as possible to avoid the players finding them frustrating and, in the end, viewing the experience as rewarding. Cy_Borg is also a high-technology setting, and the players know where they need to be and what direction they should head, so exploring a dungeon really isn’t all that appealing unless they consciously choose to view it as a side quest.

So, I started by creating a list of my goals and dug into the DM resources I have accumulated over the years. Notably, I remembered a sewer section in an old Shadowrun module I had called DNA/DOA, which had a similar goal. While the mechanics in that adventure weren’t what I was looking for, they gave the idea to abstract the sewers. With the goal of running the sewers as an abstraction, I remembered an article about mazes by Craig Payne on Exploring Infinity called “Building a Better Labyrinth – A Maze Mechanic Idea.” In it, he describes a system that uses a standard set of playing cards to “explore” a maze. This is perfect for the context because it can be handled quickly at the table with a few random encounters, gives a physical representation of how much further the PCs need to travel (number of cards remaining in the deck), and conceptually it represents the choosing a passage in the right direction, rather than a cardinal direction that the PCs would already know.

Tweaking for Cy_Borg

But because the mechanics were designed for a fantasy setting, arguably something crunchier and more combat-focused than Cy_Borg, I decided to adapt them a little. If you haven’t already, please read Craig’s original article, which will further help explain the core mechanics. In addition to the core mechanics, I had a couple of goals I wanted to achieve as well:

1. Insert some opportunities to speed up the encounter

2. Ensure traps are telegraphed in some way

3. Adapt the CR mindset to the Borg system for monsters and traps

Cy_Borg Adapted Mechanics

The Play Cycle

1. Start by placing four cards face down on the table.

2. PCs decide which direction to take.

3. Reveal the card and consult the core mechanics table to determine what the card represents and its effect.

4. Deal the next passageway’s options face down, above the current ones.

5. Repeat steps two through four, removing the cards for any room older than the last and putting them into the discard pile.

If all options at an intersection are a dead end, return to the previous room and role-play a secret door scenario revealing another card. The final destination is found when no more cards are left in the deck.

Traps (d10)

1. A rush of water pushes PCs back to the previous intersection, cutting off the passage and requiring another selection.

2. Clusters of bright orange fungus growing on one or more corpses. Any disturbance triggers a spore explosion, releasing a Wraith (Mork Borg) that attacks.

3. A column of light. When a PC enters it, they are frozen, and an evil duplicate of them is conjured. The victim is only freed when the duplicate is killed.

4. An old rope bridge crosses over a 30-foot drop into a room below. The bridge looks to be in iffy condition. It snaps if more than two characters are on it at once.

5. A giant swinging blade that must be passed through to progress. Visible pressure plate on either side. Blades are triggered when a pressure plate is released unless the other plate is also depressed. Going slow poses no risk.

6. A pressure plate on the floor; depressing it triggers an alarm that attracts enemies (roll on the queen combat encounter table)

7. A giant metal skull with a gem in its open, toothy mouth. It bites anything put inside.

8. A sealed door with two identical handles on the adjacent wall. One releases snakes from above, and the other opens the door.

9. A giant cauldron filled with treasure. Any weight added to the cauldron causes the lid to slam shut and a fire to spark to life underneath it.

10. Fungus that surrounds the walls and ceilings. The air shimmers and appears hazy. Entering the haze with a flame ignites the air, turning it into a ball of fire.

Combat Encounters

Jacks (d4)

1. A Berserker (Mork Borg)

2. d2+1 Headhunters

3. d2+1 Stinger Drones and a Gang-Goon

4. d2+1 Blighthusk

Queens (d4)

1. d2 Doppel and d2 Stinger Drones

2. d2+1 NanoGoons

3. A Turret and d2 Flyer Drones

4. d4+1 Vamps

Kings (d4)

1. 2d4 Vamps

2. d4 Berserker (Mork Borg)

3. A Krok

4. d4 Grotesque (Mork Borg)

Safe Area (d4)

1. Cred stash (3d6 x 100 creds)

2. Drug stash (4x rolls on the drug table)

3. Weapon’s cache (Pick random weapons)

4. Shortcut passage, Burn half the card deck

My Revisions

To meet my goal of making the play experience swift and rewarding, I added the Jokers into the deck to represent shortcut passages, allowing the PCs to skip a bunch of intersections and shorten travel time. Secondly, monster encounter tables have been added and scaled to make the difficulty variable but quick to jump in and out of. Finally, to avoid traps feeling unavoidable, I suggest using the methodology discussed in the Bastionland blog article 34 Good Traps, which helped inspire the table I created.