måndag 1 april 2019

The clue probability rule

(I'll return to posting gameable content shortly.)

Most everyone on the internet is familiar with Alexandrian's three clue rule. The stipulation of that rule is that players are likely to miss some of your prepped content, which also includes any given clue. So to give the players a decent chance of progressing through a investigation-adventure, you need more than one clue leading to the conclusion, or to any breakthroughs that eventually lead to the conclusion. True to its name, the rule states that the perfect number of clues for each breakthrough is three.



I like this rule, for two reasons.

First, it means that each breakthrough is overdetermined: there is more than one path leading you there. This, to me, was a central thing in Masks of Nyarlathotep. You had a hunch from the beginning that you were going to Africa, but it felt very distant and hard to justify - what were you going to do there? With each new clue, you became more and more confident that you were actually going to Africa, up until the point where it seemed like the only reasonable thing to do. So basically, each new clue reinforces those you already have. Maybe you were already sure that Mr Vardis was a killer, but confronting him at this point seemed to carry so high costs. And then you learn that he is about to strike again, and suddenly acting becomes more urgent.

Second, and conversely, it also gives the adventure a branching structure. As there are always too many leads to follow up, the players will have to prioritize and consider what-if scenarios. Once the killer is caught they have perhaps seen 75% of your prep, so they still might not know what was the deal with Mr Vardis' prize-winning kennel. This makes the world seem bigger and the mystery more engaging.

In sum, the three-clue rule recasts a linear adventure to a dungeon-structure, where clues lead to new locations and breakthroughs in the investigation much like doors and corridors lead to new rooms.

However, this also shows some problems with the three-clue rule.

If we take the dungeon analogy seriously, we should accept that it isn't just a version of a linear adventure. Most dungeons don't have a straight-line progression to the end. And most dungeons are ok with you not reaching the end. If we were to apply these aspects of dungeon design, there would not always be three clues leading to the next revelation. Often there might just be one, and sometimes it would be hidden. And if the PCs don't find it they'll have to backtrack or even give up. And other times there would be clues that lead more than one step ahead in the investigation. So instead of 3 clues leading to A where 3 new clues lead to B etc, you'd have something more akin to a web.

However, even if we switch up our three clue investigation in this way - making sure that there are not just clues leading from A to B but also clues from B to A and from A to B via X and Y - we run into the problem of direction. Once you've reached C, it makes little sense to return to A because C is closer to the final conclusion than A. This is the same as in a dungeon, where you progress from the point of entry towards the central treasure through deeper and deeper levels.

If you want an even greater level of freedom in your investigation, your clues must be meaningful even in the presence of other clues. This is the rationale behind the guess-who structure and the triangulation (or venn-structure, as Kyana pointed out), described earlier. Here, all clues carry equal weight so as long as you're still uncertain about the solution, you gain from seeking and finding new clues.

For this type of investigation, I'd like to propose another rule for clues: the clue probability rule.

For each conclusion that you want the PCs to make, include a clue that they have a probability of finding whenever they make an effort to find it.

Say that you have a murder weapon: a knife with a easily recognizable look that would lead you to the smith who made it whom in turn could provide a list of clients. The knife must be somewhere. So we decide that it is in the pond, close to the scene of murder. Now if the PCs would look in the pond, they would definitely find it. So the clue probability is 100%. But perhaps they don't, because how would they guess that it is there? Instead, they might investigate the wounds. They can determine it's a knife without problem, but could they also conclude that this type of knife is made by Brambly the smith? I dunno. 1 in 6. Otherwise they just learn that the knife must have curious proportions. So maybe they ask a smith, or an assassin for help. 1 in 3. Or ask witnesses. 50% chance. The scrap-finder kids or pawn shops? 10% per day has passed since the murder. And so on.

The point here is that instead of designing several clues leading to the same conclusion (or in addition to), you design a clue that there's always a chance of finding whenever the characters make an effort to find it.

So now we have a hierarchy of blueprints for investigation adventures

The linear structure. A breadcrumb trail where A leads to B leads to C. Fail-safe if clues are not hidden behind roll to continue. Very little agency, built in story arc.
The three clue structure. A breadcrumb trail where multiple clues lead from A to B and multiple clues from B to C. Almost fail safe, given the plurality of clues to each conclusion. Some agency, allows for story arc.
The dungeon structure. A web of breadcrumb trails leading between A, B and C through multiple clues. Failure is unlikely. Good agency, story is largely emergent.
The open structure. A limited set of clues of equal (or similar) importance, which can be found through many different approaches. Failure is possible. High agency, no story arc.

Map + clues



Here's my campaign map, or the SE quadrant of it.  New things are added as I prep them.

My campaign consists of three layers of adventure, superimposed.

At the bottom layer, there is a square crawl. Given the vast number of possible location, any content existing on this level is very likely to be missed. Because of this, the square crawl basically relies on tables for content. This means that I can have a dozen towers on the map and only have content for six of them, or hundreds of wilderness-squares and only content for twenty. So far, my players have engaged with the square crawl exactly once so this seemingly limited content is actually plenty. If I were to run out, I'd write more. Until then, it's just a waste of prep time - especially since d4 Caltrops got everyone's back.

At the second layer, there is a point crawl of locations connected by roads or trails. This is what my players mostly engage with so this is where I focus most of my prep. At the points of the crawl are adventure locations, set piece encounters, small scenarios or key NPCs. Here I also slot in adventures made by others when I find some that fit my aesthetics and tone well enough. So we've played Curse of the Shrine Goddess in this way, and I've placed a couple more.

The final layer consists of an investigation-mystery that provides the default point of engagement. This is basically a poor-man's CoC, with handouts containing clues for the central investigation into the relics of St Severend/Severinus as well as other mysteries more related to the history of the campaign setting (Why did Severend's holy mission fail? What happened to the Witch King? These kinds of things).

The third layer is the reason for my interest in different clue structures. Previously, I've outlined the elimination or guess-who structure where each clue cuts the remaining possibilities in half. This allows you to eliminate options until you eventually only have one left, which is the correct answer. The method have survived the first contact with playtesting: in Sourn, my players DID figure out the who the murderer was in about two hours without any pointers from me, DID NOT perceive the underlying structure, and were consequently super impressed with their detective skills and their luck. A great success (and a secret they must never know)!

So with the guess-who structure seemingly doing its job, it's time to introduce a second structure: the triangulation. The idea of triangulation is this: if you don't know where you are but can observe some landmarks whose position you are familiar with, you can use their bearings to determine your own position. So if your first clue is "east of X" and your second clue is "south of Y", you basically have the row-column coordinate of the thing you are looking for. You could also use it for social relations: "relative to Mr X" and "co-worker of Ms Y".

Here's a version, using distances instead of directions, which creates two circles with the target at their intersection. (Note that unless you're super skilled at measuring you'll probably end up with circles that intersect twice, so you'll need three distances or some constraining factor). Travel speed is 18 mi per day. 

The Saint's Hand 
No sooner had Severinus died, than many accounts began to come of miracles because those who touched his severed hand regained sight if sightless or speech if speechless, and those who had terrible coughs could again draw breath like young people. After five days at a stake in Mersault, the hand was taken down in secrecy and smuggled to a tomb seven days’ travel by road from there, and Ygdrain was powerless to find it. 

 “A swollen tongue” – Excerpt from traveler’s log 
At one time my tongue became uncomfortably swelled up, so that when I wished to speak it usually made me stutter, which was somewhat unseemly. I went to the tomb of the Saint’s Hand, eighteen miles from Croix-an-Tour as the bird flies, and drew my awkward tongue along the wooden lattice. The swelling went down at once and I became well. It was a serious swelling and filled the cavity where the palate is. Then three days later my lip began to have a painful beating in it. I went again to the tomb to get help and when I had touched my lip to the hanging curtain the pulsation stopped at once.

fredag 29 mars 2019

1d8 horrible wilderness encounters


Things to encounter in the horrible wilderness. Inspired by Goblin Punch, who is always a source of inspiration.

1d8 wilderness encounters

1. A great wolf (4HD, L, claws: 1d6 dmg) with its lower jaw missing, slowly starving to death.
2. A great elk (6HD, H, antlers: 1d6+knockback, trample: +1d6 dmg on charge attacks, mv 8), deformed by bulbous tumours spreading across its body.
3. A sounder of great boars (3HD, L, 2 armour, tusks: 1d6 + knockback, trample: deals +1d6 dmg on charge attacks, mv 9), driven to madness by foot-long leeches gnawing through their pelts (0HD, T, maw: 1 dmg, increasing by +1 per turn).
4. The severed head of a great wolf continues to hunt, moving by force of will (3HD, claws: 1d10 + bad luck: save or all rolls HARD until curse dispelled).
5. A giant bear-like creature (6HD, H, claws: 1d8 dmg + save or 1d6 poison) with a gaping wound in its side. Powerless to stop the gathered crows from eating its exposed flesh, it still lashes out at anyone approaching. Crows (0HD/3hp, S, beaks: 1d4, flurry of feathers: actions are HARD when attacked by the crows). Stuck in the wound is a bronze bog-folk spear: 1d10, long, impaling: prevents the target from using a single ability, for as long as the spear is stuck in their flesh.
6. A decaying unicorn, its white fur falling off in tufts and blood running from its muzzle (6HD, horn: 1d10 + piercing, cursed: a character suffering damage from the unicorn horn has a randomly determined ability deteriorate by -1 each round until successful save or dead, abomination: if killed, all characters gain +1 SPI).
7. A tall woman with raven wings like a trailing cloak of black feathers where her arms should be and skin crawling with parasites. She is capable of short bursts of flight, after which she crashes to the ground in a cascade of black blood and vermin, out of breath. Lady of Decay. 4HD, L, talons: 1d8 + piercing, black vomit: targets 6 squares in straight line, save or 1d6 poison damage, demonic: 2 attacks per round, mv 9. Limited flight: can fly for a single round, then crashes to the ground dealing 1d4 damage + no armour to anyone below and an equal amount to herself, roll 1d8 for scatter to determine her point of impact. Parasites: when the Lady of Decay suffers damage, any adjacent character must evade or be attacked by 1d4 parasites (0HD, T, maw: 1 dmg, increasing by +1 per turn).
8. Lord of Hunger. An albino elk with the face of an old man (8HD, H, antlers: 1d8 + knockdown, trample: +1d6 dmg on charge attacks, breath of flies: 1d6 + save or all actions HARD, range 12/cone, mv 9). It speaks with a tortured voice, offering power in exchange for humanity. If a PC accepts, the Lord drinks a pint of their blood draining their soul of 1d10 SPI. This grants the creature the ability to cast spells and makes it immune to all attacks from the person whose blood it drank until next new moon. If the PC survives, the creature bellows with sudden rage “Now you know!” and sets off to hunt. Until the PCs reach a sanctuary, encounters chances are doubled for wandering monsters.

torsdag 28 mars 2019

The Hangman Trap

The road through the waterlogged forest curves slightly, yielding to a small cliff. A solitary tree in the bend towers high above the surrounding shrubbery. Dangling from its branches is a hanged knight, the toes of his sabatons just out of reach for a person standing underneath. You enter in the low-right corner.


Target 11
X = Dead knight, hanged from a large tree. A great helm covers his face and shield and tabard is missing, preventing identification w/o first lowering the body. A golden necklace gleams from the broken neck.
- - = Pit trap, meticulously hidden, covering area under knight and 2" radius (1d6 damage, no armour).
o = Bandits. 2HD, leather armour (2) & shield (1d4 / +2 defense), axes 1d8+deadly: reroll ones, bow 1d6. No real interest in fighting, only in taking things.
:: = waterlogged shrubbery, small trees, reed. Movement halved, provides half cover (full cover if crawling)
TT = cliff, STR to climb

Timer: 1d4, reinforcement. 2 more bandits arrive from the shrubbery, responding to a secret signal.

Bandit tactics (in order of preference): 
1. Hope PCs fall into pit, demand ransom for their lives
2. Reveal themselves, demand PCs surrender and give up their equipment for safe passage
3. Fire arrows from cliff to draw PCs there, signal to reinforcement to steal anything left behind (such as pack animals), then flee with the loot
4. Fight!

onsdag 27 mars 2019

Giants lived here (1d6 locations)


Here are some more locations from my campaign prep. I'm thinking I might do a post a day to commemorate the last week of Google+.
Once, Giants lived here, as evidenced by... (1d6)
1. A stone hand, the size of a full-grown man and yellow with lichens, rise out of the damp moss. A unicorn grazes in its shadow. If the unicorn is followed, the it will lead the PCs to their original destination safely and within hours. A character eating its flesh gains +1HD but loses -1 SPI.
2. A pictogram of a very large figure, possibly a queen, chiseled into the side of a flat rock. The pictogram is partly overgrown by ferns and pine-roots; if cleared, anyone touching its crown will receive a blessing (1 reroll, to be used at any point), unless sworn to the New Faith.
3. A large heap of stones, possibly a grave of old. Among the stones live a large gulon (HD 2), its diet of ancient bones and cursed gold having rendered it near deathless. If reduced to 0 HP by ordinary weapons, it returns to life in 1d6 rounds.
4. A giant skull, overgrown with moss to the point of appearing as a boulder, where 2d4 owl-gnomes live (4HD, hatchets: dmg 1d6+piercing, agile: HARD to hit, small/-1d8 but fights as medium size). Cruel and cunning, they will use trickery and guises to lure travelers into their lair to be butchered.
5. Between unnaturally square boulders lives a bramble-beast (7HD, Bark skin: as plate, Crushing blow: 1d10+knockback, Huge +2d8), almost indistinguishable from the shrubbery it lairs in. 

6. Enormous bones reach up from the mire, shaggy with lichens and blackened vines. Druids congregate here at moonlit nights, divining the past and sinking sacrifices in the dark water. On such nights (1-in-6 chance), sleep is impossible in this square; on the following three nights, double chance encounter checks must be done.

tisdag 26 mars 2019

1d4 blessed ruins


1. An old church, overgrown with moss. Inside is a magnificent organ with silver pipes, tended by shy monks who sneak in at night to play it when the Giant Bat (HD4, Bite: 1d8+poison, Flight, MV9, Huge: +2d8) that resides in the ruin is out hunting. In an unmarked grave is the corpse of Caelfarn, father of old Corwyn and agent of the Occ Empire, buried with his elfin maille (armour as mail, weight as gambeson) and blessed sword (1d8, +1d4 damage against unliving).



2. A small monument stands some twenty paces into a shallow lake, lined with bones. Blackened inscriptions on the monument declare that on this site, Holy Severinus converted 101 pagans to the true Faith.
3. Remains of a beacon tower, high as a light-house but abandoned mid-construction. The tower carries the royal insignia of Occ. In a stone sarcophagus, overgrown with weed, a knight of the second conquest lies buried - blessing the construction with his death. Five winged demons (3HD, claws 1d8, sightless) live in the upper half of the tower, defiling the holy repose with their droppings.
4. The ruins of an abbey amid a lifeless field. Its insides are black from fire, its treasures reduced to molten lumps of metal and wood. Only a charred statue of the God Mother remains, twisted by the flames. Worshipped locally as the Ash Lady, anyone kneeling before her in allegiance must make an unmodified death save. If the roll is below SPI, the supplicant gains the power to conjure flames from their blood. Each character can only attempt this once in their life. A squire (2HD, leather & helm, axe 1d8+deadly, shield 1d6) sits brooding by a small fireplace; loyal to Guiselbert the Bold he came for the idol's aid in freeing his master from the Black Knight, but has yet to find the courage to endure its deadly trial.