Stages of Mystery is my idea for a subsystem that deals with investigation.

The main problem that I've found is to define the kind of process that the system is supposed to model, so I've decided to post my objectives/directives as well:

• Getting pieces of information won’t solve the problem on itself but will advance solution. In order to accomplish this, there must be several stages of resolution. These will be the Stages of Mystery, which means that this subsystem is meant to deal with successive discoveries, unveiling linked mysteries, each of them a challenge on its own.
• All information is precious – all data add dice.
• False leads are as good as bad ones… on the long term. No, not leads, conclusions – dice that do not help solving the enigma roll over to next roll.
• Mechanically speaking, should solving the mystery be easier or harder as long as the story unravels? What I'm having in mind seems to create mysteries where it's easier to solve the first stages while gathering the scattered clues is harder; on the last stages, this is reversed and it's easier to know what's going on (impending revelation), but getting the last, critical clues is harder.
• Player input - picking new lines of investigation or research, have to narrate conclusions, need to follow directions from dice roll.
• Mysteries are meant to be resolved at some point.

Ok, so, my basics:

d10s. I love them to death.

GM - Player who has scene-framing, setting-building power and plays NPCs.
Narrator - Player with narration rights.
Base system - system that Stages of Mystery is to be plugged on.
(Match) Set - group of dice that have the same number on a roll.

Starting a Mystery

* GM sets a Mystery by placing a d10 with a value from 3 to 5 (recommended), showing it to the group (this die isn't considered part of any Investigation roll and doesn't actually need to be a die, of course; tokens or just writing the number on a piece of paper would work just fine). This number is the Mystery Stage and also indicates how many linked mysteries -named Stages of Mystery- the GM has or wants to be framed. By doing this the GM informs there's something to discover here. This doesn't have to equate that there is a full plot to uncover already created but one to be unfolded and explored; this is supposed to work on GM-less games as well as traditional GM-driven games, regardless of pre-written scenarios/mysteries; Narrator will narrate the form this initial mystery is hinted at PCs.

On a prepared mystery, the GM will devise a number of linked mysteries equal to initial Mystery Stage. Depending on system and fiction, of course, players don't need to involve their characters with this proposal, but there might (and should).be a reward of some kind.

* First Narration rule: Nobody can't challenge what it has been narrated on a previous Stage, just modify it if necessary and interesting.

* On a scene, characters can get Pieces of Information, pending GM approval. For every Piece of Information gathered, add a die to an Investigation pool. Actual in-game clue-gathering is resolved by Base System, narrated by Narrator. GM tells characters how many Pieces of Information can be collected on a scene (offering/moving forward a number of dice equal to that amount).

An Investigation dicepool can't have more dice than Mystery Stage + 1; Kept dice [read below] are not considered for this limit. This is because the dice roll ensures players than current Stage of Mystery will be Resolved when having MS +1 dice.

* On a Resolution roll, group rolls their Investigation dicepool. Group can't Resolve if current Stage Investigation dicepool is 0, regardless of Kept dice.

If any die is higher than Mystery Stage or there are any Sets, this Stage is Resolved. Each die above the first on a Set grants the group a Clue that the GM provides; this is counted for every Set, in case there is more than one. This is to represent the PCs connecting the dots and gaining greater insight than just the sum of evidence. Players can (and should) use Clues to decide next steps.

* Any die lower or equal to Mystery Stage is considered a flawed conclusion and this has to be addressed by the group, Narrator narrates this with input from GM if necessary. These dice can be part of a Set, which is valid for Resolution and Clues. These dice are considered Kept if the roll Resolved the current Stage of Mystery.

Kept dice are added to next Stage's Investigation dicepool - doing this is narrated by any player (Why? Haven't you seen House?). Note how many Kept dice are added to an Investigation roll, because on an Unresolved roll, Kept dice aren't spent. If the roll Resolves, all added Kept dice are no longer considered such, although that roll might grant new Kept dice.

* In case the roll doesn't Resolve the Stage of Mystery, group can roll again until resolution, but in-fiction events and other considerations might apply; an optional rule is to reduce Investigation dicepool by 1 per Unresolved roll - an example would be when characters are using evidence that becomes obsolete between rolls. Characters can look.for more Pieces of Information between Resolution rolls.

Example regarding last two points: Group has 4 Kept dice and decides to add 2 dice to a Resolution roll, yet that roll doesn't Resolve; Kept dice are still 4. On the next Resolution roll, group adds 3 dice and that roll Resolves the Stage. The roll produced 2 Kept dice, so now the group has 3 (4[initial] - 3[used] + 2[gained]).

Moving to the next Mystery

* Kept dice are counted and recorded.

* Investigation dicepool resets to zero.

* Mystery Stage is reduced by 1. Adjust die, tokens or notes to reflect this!

* Resolve new Stage. Remember that Investigation must be raised at least to 1 before resolving a Stage.

Final Revelation

* When Stage of Mystery 1 is resolved, Final Revelation is due. Since, mechanically speaking, any Piece of Information resolves the puzzle, only Clues can be achieved at this stage - group has to take everything into account and provide the answer themselves; dice won't put all the pieces together for them. In other words, there is no Resolution through dice.

* Investigation still needs to be raised to 1 ("ok, we know your father did it. where is he?")

* Notice that it's unlikely that there will be Kept dice to add at this point. Also, that, since it's the finale, the mechanics prevent this from happening for next Stage - there isn't one

Preliminary analysis of player input

On first Stages players will have characters getting as much information as possible; characters matter more than players. Besides, characters are not aware of the scope of their actions, whlie players do, since they know what Stage of Mystery they are.

As the game progresses, Clues are more crucial, since Kept dice will be progressively reduced. Clues tell players where to look at, who to talk with... players gain prominence. Since Mystery Stage is lower each stage, players might either feel less Pieces of Information are needed or more is better, since it opens avenues for Kept dice and Sets - player decisions start to matter more and more.

Since Investigation dicepool is capped by Mystery Stage, at some point the choices to get crucial clues must be enforced on game, because players and characters will run out of options. "Kill me and you'll never find out the truth" is more dramatic on Stage 3 than 5...

And now a couple of fancy optional rules

Antagonist - Oh, yes, an antagonist. An antagonist is an NPC or faction that doesn't want the Mystery to be Revealed and might try to act against PCs if and when aware of their investigations.

GM will get a good old-fashioned d6 (a d4 when playing a less antagonistic game). On every Resolution roll the GM will roll that d6: if the roll is higher than Mystery Stage, the Antagonist becomes Aware of the group intentions and activities, gaining an Awareness Rank. The more they roll, the more chances the Antagonist has to become Aware.

Since Antagonist's main goal is to keep things quiet, they won't act against the group... immediately. Antagonist reactions are determined by the following, proposed table:

• Rank 1: Antagonist has heard about the group activities and has an eye on them.
• Rank 2: Antagonist knows the group is on the track. Might act indirectly against them, which can provide 1 Piece of Information.
• Rank 3: Antagonist realizes the group is a threat and will do anything to get rid of them, even taking direct action. This could provide up to 2 Pieces of Information.

Antagonist actions are resolved through Base System.

Modifiers - Since this is a plug-in subsystem, playing groups should take Base System into account and develop a set of coherent modifiers depending on rolls or stats, ranking on 1-3 as a bonus or minus. This is on a per-character basis. This modifier is applied on Investigation rolls as follows:

Bonus: group can adjust dice on a roll, lowering or raising a number on a die by 1 per Bonus rank. This can be applied on multiple dice. Group uses only the highest character bonus score.

Minus: group has to remove 1 die per minus rank if the PC is on any scene that contributed to gain Pieces of Information. Use the less detrimental minus score. If a character has a bonus that applies to that scene, their minus score is 0.

And, to add those together, remember that the Antagonist might or not have taken measures to guard the secrets players will be unveiling, so adjust the Antagonist roll accordingly, too. Base Antagonist modifier as per Base System.

Next time, an example... a D&D-ish example!

Using the House example, you can even consider the medical issue to be an antagonist to the players.

In this situation, the players offer suggestions and experiement, but if their plans go awry the patient gets worse as the medical condition reacts in new ways.

This may bring the patient closer to death, but it reveals vital new clues about what's happening.

This is heading in the right direction and I'd love to see that D&D example.

V

Using the House example, you can even consider the medical issue to be an antagonist to the players.

In this situation, the players offer suggestions and experiement, but if their plans go awry the patient gets worse as the medical condition reacts in new ways.

This may bring the patient closer to death, but it reveals vital new clues about what's happening.

This is heading in the right direction and I'd love to see that D&D example.