Tabletop Roleplay Encounter Design

The Lunar Space Station Copernicus

          I knew my weaknesses as a storyteller and dungeon master: I could not voice act very well, and I could not handle heavy improvisation. I also was working on a personal story-based project in conjunction with this, so I already had a highly researched setting that I could take advantage of. It felt very natural than to combine the two and design an encounter that would utilize my research that also attempted to cover for my weaknesses.

          I had done a lot of research into the Moon, what, where and how we might settle on it, and what a large scale and settled and lived-in city on the Moon would look and feel like. As much as I wanted to design an encounter in the city itself, there was no way that I could account for everything my players would want to do without obviously railroading them, and as stated before, I’m not very good at improvising on the spot. I decided then that I would take it one step higher and have them play in a space station circling the Moon.

          This would solve my obvious railroading issue in a lot of ways very naturally; what better way to keep players in check than putting them in a fragile metal box surrounded by a deadly, empty void? It also wouldn’t feel as forced since this is a regular danger and constraint that astronauts just have to deal with. Next, to deal with my voice acting issues, but also because I wanted to spice things up a little, I decided on having one other NPC that you can talk to: an AI called HAYLI. Using text-to-speech, an already defined list of responses, and Microsoft’s built-in text-to-speech voice Zira, I would pilot the ship AI, the fourth crew member on the space station. This name was intentional. I wanted to take advantage of existing prejudices against AI characters in our pop culture (HAL from 2001: Space Odyssey) and have players wrestle with that over the course of the encounter. It would also be an interesting challenge to write and pilot because I would have to predict potential circumstances and conversations that she would have to respond to. While writing her, however, I did not want her to fall into the bad-AI trope. I wanted her to be trustworthy and ultimately on the players’ side (though they might suspect her). Because of this, I had to devise a new source of conflict. I’ll get to that in a bit.

          First, to rouse my players’ suspicions, I figured that I should have things go wrong on the station and make it seem like it was her fault. Then I had to push players into a situation where they’re cut off and vulnerable. I decided then that the premise should be that the station was preparing to dip into a Dark Zone, a part of the station orbit path that is devoid of satellite coverage. This would be a known event and something that the players have been tasked to prepare for, but right before they enter the Dark Zone, things would go wrong and perhaps start a little in-fighting. To aid with this, I gave each player secret information (they each knew different things about the ship. For instance, Kira had an antique revolver stashed in her bunker, and Solu knew that he could rig the station reactor to blow). I would script the conflict so that players would most likely ask Command to send for aid. This aid would instead reveal itself to be an ambush. When their ship docks, the players won’t get the help they’re looking for and instead have to deal with several armed threats while they themselves were relatively unarmed. What are the invaders after? I decided to introduce another objective: a radioactive, self-replicating material that is highly coveted and top-secret.

          Final conditions:

  1. Survive the Dark Zone (4 hours)
    1. Don’t all die, don’t run out of oxygen, etc.
  2. Survive the Invaders (2 hours)
    1. Don’t all die/get captured
  3. Optional: Keep the lab material safe.
  4. Optional: Keep HAYLI safe.

Roleplaying 101* (A simplified roleplaying system)


Here is the basic list of skills as an astronaut:

  • Trajectory (throwing, aiming, etc.)
  • Maneuvering (Zero-G navigation, acrobatics, etc.)
  • Athletics (stressful physical activities)
  • Stealth (sneaking around, sleight of hand)
  • Wit (general book knowledge, hints from storyteller)
  • Medicine (first aid, physiology)
  • Computers (using technology, hardware/software)
  • Repair (fixing things, breaking things intentionally, crafting)

There are fewer stats here because the game will be more a puzzle-like and dependent on the player’s ability to describe their actions. Player characters are also all accomplished astronauts, so a special set of skills are required.

During skill checks, well-roleplayed actions will receive advantage (roll twice, pick between the highest), while other times, due to circumstance or poor execution, there will be disadvantage (roll twice, pick the lowest). Add relevant skill points to the roll. A 1 or a 20 automatically fails or succeeds, respectively.

          Every player starts with 4 health. At 0, their character is unconscious. At -1, they’re unstable, and at -2 they die. An unstable character perishes after an hour without medical attention. If your character is ever exposed to space without being properly prepared, they become unconscious and die in 5 minutes.

          Human life is fragile.

          During combat, there is no definitive order. A player acts, and the opposition reacts. Players and the storyteller can decide organically who to go next, and the opposition will retaliate.

Player Characters

Name: Dave


Systems Analyst

Skills                                                Skill Points

Trajectory                                                            -1

Maneuvering                                                        1

Athletics                                                              -1

Stealth                                                                  6

Wit                                                                        3

Medicine                                                              4

Computers                                                           8

Repair                                                                  5


Portable computer with various ports and custom diagnostic software, battery pack, flexible pipe camera, pouch with computer hardware tools (tiny wrenches and screwdrivers, solder, and anything else within reason), 50ft grappling tether, flashlight

*(As long as you have your portable computer, you can Hack things using your Computers skill)

*(You know that the Terminal room has a circulation of coolant on, making the ground foggy. You can manually activate or deactivate most of the ship’s systems here, including lights, fire suppressant, doors, node detachment, etc.)

*(You know that there is a highly radioactively, self-replenishing substance that you all are studying in the Laboratory. It is currently top secret.)

Name: Kira


Skills                                                Skill Points

Trajectory                                                            5

Maneuvering                                                        6

Athletics                                                              3

Stealth                                                                  4

Wit                                                                        1

Medicine                                                              8

Computers                                                           -1

Repair                                                                  -1


2 cans of spray-on coagulant, Bandages, and Ethanol, Suit Repair kit, pouch with small medical tools (scalpel, tweezers, anything else within reason), 70ft grappling tether, flashlight

*(You have a hidden cache in your bunk with an antique 6 shot revolver in it. Nobody else knows about this)

*(You know the Med-bay has a portable defibrillator, fire extinguisher, and emergency oxygen tanks, among other medical supplies)

*(You know that there is a highly radioactively, self-replenishing substance that you all are studying in the Laboratory. It is currently top secret.)

Name: Solu


Skills                                                Skill Points

Trajectory                                                            4

Maneuvering                                                        3

Athletics                                                              5

Stealth                                                                  -1

Wit                                                                        6

Medicine                                                              -1

Computers                                                           1

Repair                                                                  8


A pack of Industrial Strength gum, 2 spray cans of rapid-expanding sealant, compact toolbox (wrench, several screwdrivers, and anything else within reason), 50ft grappling tether, flashlight

*(You know there are heavy duty space suits in several docking areas, thick and equipped with blowtorches, high-strength arms, and space debris harpoons)

*(You know that the reactor can be shut down or overloaded and detonated in 12 minutes)

*(You know that there is a highly radioactively, self-replenishing substance that you all are studying in the Laboratory. It is currently top secret.)

Notes before a Narrative description:

          This campaign has a time element to it. When players roll to perform an action under pressure, I will usually allow it to succeed, however, low rolls will cost time. Fire may be spreading, enemies might be patrolling, and how well they apply their abilities will determine how they deal with the scenario and what the potential consequences are. I utilize failures as well as poor, marginal, and resounding successes to move the story forward.

          Combat is very fluid. Players decide on actions to take, and then the opposition will retaliate in response. There is no initiative, and it is entirely up to the players and myself to determine how the combat plays out.

Narrative Detail:

  1. Command phones in. They ask how Dark Zone preparations are going.
  2. HAYLI asks if they would like to run final diagnostics. They agree.
  3. In the distance they hear a familiar noise: an airlock has flung open.
  4. Command says they can send back-up if needed. HAYLI advises that they investigate.
  5. Solu and Kira both identify their roles as engineer and physician and volunteer to go check out the problem.
  6. Suddenly the door behind them closes. The airlock is engaging for some reason. They communicate with David and ask for assistance. David figures he could hack the door open.
  7. As David passes by the Oxygen Generator, almost as if on cue, there was a small explosion that started a small fire and rendered the Oxygen Generator offline.
  8. Back to Solu and Kira, all the air in the room has escaped and the airlock is opening. Kira finds the manual override and closes the airlock, the air is returning slowly to the room, albeit a bit smoky. The doors unlock. HAYLI recommends checking out her main terminal since she cannot diagnose the problem for some reason. She also recommends dealing with the fire, as it is reducing the air quality in the station.
  9. Kira recommends searching the Med Bay for a fire extinguisher. David searches for it and finds it quickly. Meanwhile, Solu and Kira go to the Med Bay to get the emergency oxygen tanks, just in case.
  10. 20 Minutes until they pass into the Dark Zone. As David attempts to put out the fire, they hear another airlock open in the distance.
  11. Solu communicates to everyone what he knows about the ship, that he has heavy duty space suits, that he can rig the station to explode, and that there is a top-secret material in the Lab. They collectively believe that somebody that they do not know about is opening the airlocks.
  12. Solu and Kira equip heavy duty space suits. 10 Minutes until the Dark Zone. They hear another airlock fly open. David decides to contact command and request back-up. Command informs them that help will arrive in 2 hours.
  13. 5 Minutes. David wants to check the Main Terminal for sabotage. A high roll, he quickly spots a tiny USB stuck into one of HAYLI’s terminals. David pulls it out, and the airlocks seem to open slower. HAYLI isolates the virus.
  14. Solu and Kira work on fixing the doors. David suits up.
  15. Suspecting that there is an intruder onboard, Kira gets her antique revolver from her Bunker. HAYLI is displeased but will be flexible. Kira asks her to check the cameras for anything suspicious.
  16. Solu fixes a door and recommends checking the Lab. Solu keeps working on the doors, Kira and David are in the Lab searching.
  17. Spotless, it seems like nobody was here. Solu wonders what the enemy’s motive is, whether it is to kill them all or steal the material, or both. David wants to double check HAYLI’s terminal to make sure she isn’t lying to them.
  18. Solu thinks that the most efficient way for the intruder to kill them if there is one, is by rigging the reactor, so he is making his way towards the reactor room.
  19. David rolls low on his first attempt. HAYLI remarks that she has no interest in sabotaging herself. Solu takes the outside zip line to the reactor.
  20. 15 minutes until help arrives. HAYLI sees a ship in the distance. David hails them, asking them to identify themselves. For a while there is silence. The ship looks like a rescue shuttle at least. Then they hear an answer, asking to know where on the station they are currently. Kira warns everyone not to answer. David asks why they want to know. The ship responds, asking if the lab materials are secure. The shipmates again do not respond.
  21. The ship docks in the docking bay next to the return shuttle. As they enter through the airlock, they see through HAYLI’s cameras that the suited figures lack insignia and that they are armored and armed with stun guns and batons.
  22. Kira suspects they will head to the lab. The intruders have forced their way in, but HAYLI has selectively locked the doors to stall them. The crew keeps the option to blow up the station in the back of their minds.
  23. The crew discusses their plan of action. Meanwhile, the intruders have broken through a door. They also have a skilled computerist, it seems. Kira devises a plan to avoid them: wait for them to make their way towards the lab and slip by them unnoticed by using the outside connections on the space station.
  24. The crew wonders how important the rock is to them. HAYLI values their lives more than the material, however, she does note that there might be dire consequences if it falls into the wrong hands.
  25. The invaders slowly make their way closer. Kira decides to take the lab material with her. David decides to try to take HAYLI with them on his personal computer since they’re going to try to blow up the station.
  26. Solu thinks about starting the overload sequence on the reactor, but I remind him that they would only have 12 minutes to work with if he started it now. Solu thinks of a solution to rig the reactor to blow using a trigger of some kind that he starts making using the material in the room. David starts the procedure to port HAYLI.
  27. Meanwhile, the invaders have broken through to the bunkers, and have started to fan out. The largest invader starts patrolling in a circle the bunkers and the gym, and the other two make their way through towards the Main Terminal.
  28. Solu makes the trigger, and now that the reactor is rigged, he leaves and seals the door with his blowtorch.
  29. Kira makes her way on the outside connection between the lab and the gym, taking the lab material with her. Because of the rotation of these areas, she decides to use her grappling tether, just in case. And justly so; while under pressure, she slips up a little and dangles precariously, secured by the grappling tether. It’s taking her longer than usual to cross the connection.
  30. The invaders have broken through into the Main Terminal. David hears them coming. The port is about 80% done. David tries to hide behind some terminals, but he also wants to be able to keep an eye out for what they’re doing. One of the invaders stops and waves to the other to keep going. While he’s there, he checks to see if the small USB is still in the Main Terminal, but it is not. He slides in another and begins to look around.
  31. Kira regains her footing and makes it across the outside connection stealthily, evading the detection of the large patrolling invader. She enters through an airlock; it makes a hefty thunk as it closes, and she’s unsure if anyone has been alerted by this.
  32. Solu, knowing where the three invaders are, decides to make his way towards his teammates. As he passes by the ship in docking unstealthily, the pilots on the docked ship notice and now approach him slowly, stun guns raised.
  33. David has finished porting HAYLI. He takes a flashlight and tries his best to throw it towards the Main Terminal door open towards the Lab, in an attempt to distract the invader patrolling the Main Terminal. It clunks on a doorway and rolls a little farther than he had hoped for. The invader in the room looks towards it, his back turned to David. However, David can also hear footsteps coming from the Lab, it seems that he also alerted the other invader.
  34. David takes his screwdriver and attempts to stab the unaware invader in the neck. Distressed, the invader turns around and whips back at David with the stun gun, but it isn’t on and he misses. The large invader has picked up his pace and is heading towards the commotion in the Main Terminal room.
  35. Kira decides to avoid the Terminal room and heads towards the ship. As she’s rushing, however, the lab material that she’s carrying around bangs on things on the way, and some people have taken notice. It seems like the invaders have figured out where they all are.
  36. Back to Solu, the pilots have their stun guns raised and are slowly approaching him. He throws the flashlight towards them to try to distract them as he rushes towards them with his suit’s power arms ready. One of the pilots knocks the flashlight aside and the other shoots and misses. Solu has now gripped them both firmly in his enhanced arm. The other pilot shoots as well and it lands, but because of his engineer suit, Solu takes 1 damage instead of 2. Both pilots are grappled and immobilized for now.
  37. David tries to take the screwdriver that’s lodged into the invader’s neck and attempt to stab him again, but he’s pushed away and the invader has regained his posture. The large invader has made his way close to the Main Terminal room but HAYLI has closed the doors to delay him.
  38. Kira sees Solu firmly grasping the two pilots. She takes out her gun, lines herself up and takes a shot. A combination of luck, skill, and circumstance allow her to nail both of them with one shot, the bullet passing straight through one pilot’s neck and lodges itself into the other’s head.
  39. The large invader hears the gunshot and turns his attention away from the Main Terminal room and makes his way towards the ship, potentially distressed that their targets may be armed.
  40. David is locked in combat with the intruder in the Main Terminal room. The screwdriver is still lodged in his neck. He tries to punch David, but he misses, cringing in pain. David tries to get the screwdriver so that he can give him another stab, but the intruder takes advantage of the awkward attempt and judo flips him onto to floor, pinning him in a hold.
  41. The doors facing Solu and Kira open, the tank-like man has made his way over and has brandished his stun baton menacingly. He seems unafraid of Solu and Kira’s armaments. Kira fires a shot into his shoulder, but he unflinchingly charges at the both of them. Solu jams his blow torch into the tank’s side and blasts it, piercing the man’s armor. He shudders, missing his swing with his stun baton, but grapples Solu, pinning him to a wall.
  42. HAYLI, seeing how David is being pinned, turns the coolant emitter in the room to high and sprays fire suppressant into the face of the intruder, distracting him. In this moment of weakness, David slips out from underneath him and runs towards his crewmates.
  43. Solu, wrestling with the giant, gives him a quick shove and whips out his rapid-expanding sealant foam and sprays it on the giant’s feet. It works surprisingly well, true to its name, expanding up to his torso. Kira takes advantage of his immobility and fires another shot, nailing him in his shoulder.
  44. David slips past the foamed man, trying for a stab with his trusty screwdriver as he passes by. The giant knocks it away before it does damage and tries to grab him in retaliation but is unable to while he’s stuck to the ground. He breaks free from his hold and swings his fists at David, but David ducks and weaves out of the way. The two intruders from the Main Terminal room have arrived at the scene.
  45. David picks up a stun gun from one of the dead pilots. The two intruders raise their stun guns and fire, one missing, the other hitting Solu right in the gut, dealing 2 damage. Kira runs towards the return shuttle and motions to her crew to do the same so that they can leave and have Solu detonate the charges. Coming from the docked ship, another intruder catches David unaware, smashing his computer onto David’s head, dealing 2 damage.
  46. Solu rushes towards Kira, preparing his blowtorch as the large intruder tries to block his approach. They crash hard, the intruder’s stun baton crashing into Solu’s neck, dealing 2 damage, which would knock him out, but before he goes down, Solu gets his blowtorch into the previous open wound he made and cuts the big man clean in half. Solu collapses halfway through the door to the return shuttle.
  47. David deals the invader with the laptop, shooting them with his stun gun. As he peeks around the corner and sees stun gun harpoons whiz by. Kira attempts to drag Solu’s floating limp body through the shuttle door, but it’s awkward and mired by a large corpse. Kira patches up Solu and shakes him awake.
  48. David takes a shot at the screwdriver-wounded. The harpoons lodge right around the neck, and the pain of the shock and the screwdriver wound knocks him out cold. The other intruder fires, barely missing. Kira retaliates, shooting the intruder in the shoulder blades for 2 damage.
  49. The last intruder isn’t going down. He fires again at David, shocking him square in the chest for 2 damage, rendering him unconscious. Solu, now awakened, charges at the last man standing and launches him hard into a wall, knocking him out cold.
  50. The crew has survived the unexpected Dark Zone encounter with everyone alive, the station relatively undamaged, and the lab material safe.


          The overt puzzle was figuring out what exactly was affecting the station. HAYLI could not override the airlock failures and did not know about the rigged explosive in the Oxygen Generator. The airlocks could be manually closed, but they would have just opened again if the problem was not correctly diagnosed. There was nobody else on the ship as far as the crew knows, and so the puzzle, although simple in solution (investigate the Main Terminal room thoroughly), was designed to make the players suspicious of HAYLI.

          This worked as intended. The players attempted to diagnose the problem by first investigating the doors themselves, but this merely trapped them in awkward situations and the doors did close again. The computer expert eventually decided to investigate in the Main Terminal room. Suspicions were roused, Kira pulled out her gun quickly, and was reprimanded by HAYLI. Things were not going as planned (but all according to my plan). Even though David solved the issue and the station was stabilized, players continued to investigate and think of what could possibly be going wrong.


          Although I was anxious having never DM’d before, I’m pleased that my predicted interest curve matched very well to the post-game curve, and that the players also had the same feelings about the game. The overall reception was positive, that I “nailed the interest curve”, it was as long as they felt like it should have been, and that they had a good time. They utilized most of the tools and skills at their disposal to respond to threats of different natures and they were thankful for the varied options available. The asymmetry of the characters was important and impactful, thankfully. Every player had to use skills they were most and least comfortable with. They employed the character specific knowledge that I provided them very well, although the computer expert player realized a little late in the game that he could take advantage of HAYLI’s control of the station.

The railroading was effective in providing players a clear idea of what their play-space and goals were. They commented that it was very clear what they had to solve. I designed the encounter knowing very clearly what my weaknesses were, and that benefited the experience. HAYLI, although heavily scripted, was flexible enough, and the play-space limited enough, seemed very responsive and a pleasant surprise to the players. At a certain point, players sort of talked to HAYLI as if she was a real player, and although I eventually ran out of scripted dialogue, it was still a success considering that they valued her presence to that extent.

The curves E and F differed only slightly since I had control over the interest curve, knowing when to introduce conflict when players have relaxed a little. I planned for the rapid evacuation of airlocks to be more of a problem, but it was quickly squelched. This led to a slower ramp up in interest, however, players were still hooked on a different problem: searching the ship and deciding whether or not HAYLI was trustworthy. When the interest dipped enough, I introduced the next challenge: the rescue ship impersonators. Their suspicions were instantly raised when I gave them a few choice clues: a pause in response, and an inquiry about the top-secret lab material. Then, due to the map design, docking next to the return shuttle created a new challenge to overcome, and the interest curve increased naturally as players got deeper and deeper into trouble. F, G1, G2, and G3 were very similar.

As a storyteller, I am much more adept at written and planned stories than improvised ones. Although I played to my strengths and got a successful game out of it, there were still things I wish I could have done better. I wish I could have given more vivid descriptions that weren’t interspersed with uhs and pauses. I wish I was more able to multitask so that I could involve HAYLI while still being able to come up with an interesting response to a scenario. I was hoping that lack of oxygen in certain rooms would go into play more, but I opened airlocks too slowly and was too afraid to improvise further. Airless would have added a nice twist, providing areas of total silence but also increased danger, and the oxygen tank mechanic I planned could have been relevant. I also intended to have the invaders take control of HAYLI to an extent, and was given the opportunity to do so but I completely forgot that I had that in mind. It would have given David a very important mission, and made the hacking enemy much more threatening and interesting (all he did was smach David on the head with his computer… a poor use of his abilities).

I also wish that, at the end, instead of just saying “congratulations you defeated everyone!”, that I docked yet another ship, new intruders flooding in, forcing Kira to drag David into the return shuttle and make Solu start the self-destruct sequence, ending the campaign with a bang, while also giving more sense of accomplishment, since they also completed the side objectives (porting HAYLI onto David’s laptop so that she would survive, and securing the lab material). I also wish I rolled better for the large invader. He was intended to be a very difficult enemy, but he literally whiffed all but one of his rolls, in spite of his powerful stat bonuses. Despite this, players still felt satisfied when they finally took down the giant enemy, and there were a lot of high stakes moments (David getting swarmed by enemies, Kira stealthily navigating the station) and stellar natural 20s (getting two kills with one bullet, cutting the giant in half right before getting knocked out cold).

Improvisational storytelling is definitely a skill that must be practiced. I could have mitigated the descriptive and ending problems better had I ran a few more test runs in my head, thinking about my responses rather than simply just what the players might do. The result of this encounter has given me new confidence and firsthand proof that a heavily railroaded experience can still be highly engaging. The railroading was what gave me the ability to control the interest curve, and the players still had lots of freedom since I gave them many relevant tools, clear information, and multiple solutions. “Within the constraints of a game, we are set free.” – a notable game designer, probably.

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