I make apps for other people

It’s elementary

Posted by Chris Jones
On August 7th, 2009 at 16:37

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Posted in Design Journal, Games

I’ve been considering what would make a good, unique quest. Putting aside Becky’s concerns about griefing, competition for mobs or clues, etc., and that this is intended for a text game (although it would work in a graphical game), I’ve got the skeleton of a design for generating mysteries that I’d like to try to implement sometime.

We’ll call it, for lack of a better term, Mystery Quest.

One outstanding question remains: do you believe players need feedback when collecting correctly clues, interviewing witnesses, and assembling evidence?

Procedural content is usually dry, obviously generated, and tends to lack any personality. Consider, for instance, the first episode of Castle: the killer didn’t just act like a serial killer, he worked to frame a victim, made the killings look like those from the book but with subtle flaws, and left a trail of contradictory evidence that was very hard to pick out from the activities of the obvious suspect. This would be pretty darn hard to generate procedurally.

The Parts of a Mystery
A mystery quest is composed of:

  • clues – items and states that act as evidence of the action and actors
  • witnesses – in these terms, NPCs who saw the action/actors or discovered the results of the activity
  • motive – the underlying reason that the activity took place
  • suspect – the actor(s) responsible for performing that activity

Assume for now that I don’t have any shell actors, that is that I don’t have plans for a system that creates cut-outs or intermediate actors (someone framed for the crime).

Starting a Mystery
I’ll use 20th/21st century terms to describe starting mysteries in the context of crimes. There’s no reason mysteries couldn’t be set in a fantasy medieval, steampunk, 19th century, or far future milieu but I choose to use language and scenarios common to our contemporary period.

Given a mystery (which I’ll describe shortly), the player needs to be notified of the mystery in some way, in a detective game by notification by the police or a client, for actions such as:

  • crime occurs; the witness notifies the police or authorities
  • witness finds a body or out-of-place person
  • victim of crime is admitted to a hospital
  • victim of crime discovers something is missing (from their home or person)
  • witness finds victim is missing
  • player character (PC) notices something is odd or incongruous (clue grants the quest)
  • PC witnesses/notices crime taking place (online or offline)
  • witness or victim expresses a worry or concern to the PC

Within each of these is some cause, such as PC witnesses/notices crime taking place may be caused by a:

  • break-in
  • mugging
  • murder
  • theft

Causes and Sources
The intersection of the cause and source defines the broad mystery. The source indicates who begins the mystery, while the cause describes what kind of crime or action took place by the actor(s).


  • player character – the PC was either the victim or witness, or obtained a clue independently
  • contact – an NPC with a relationship to the PC starts the mystery, such as a vendor NPC’s bark, the player asks the NPC for updates, or the player finds a quest indicator (such as a quest board)
  • victim – an NPC without a relationship to the PC starts the mystery (if the PC is a detective, the victim contacts the PC for assistance; if the PC is the police, the victim seeks help)
  • witness – an NPC without a relationship to the PC starts the mystery (the PC runs into the NPC; the NPC has a quest marker)

The role of victim and witness both allow the player to start the mystery but each should fulfill different criteria toward completion of the mystery.


  • missing item
  • missing stranger – an NPC without a relationship to the PC is missing
  • missing contact – an NPC with a relationship to the PC is missing
  • theft
  • burglary
  • robbery
  • assault
  • murder
  • poisoning
  • disease
  • harassment
  • treason
  • perjury
  • arson
  • property damage

For each mystery source, the time, location, witnesses, and clues need to be established.

For each mystery cause, the motive, means, and evidence need to be established.

Clues may become evidence, but clues may also be misleading.

Motives are generally soft: they don’t have a lot of meaning within the game but are needed to provide flavor for the player. Motives flesh out the NPC actors who are suspected of the crime.

  • conspiracy
  • passion
  • poverty or desperation
  • vengeance
  • vigilantism
  • accident
  • orders or job

Witnesses are a second form of evidence. While they aren’t collected like clues, they are interviewed to provide additional direction (a new location to look for clues, a victim or suspect actor, another witness to continue the narrative). Witnesses can be described using two axes:

Witness Helpfulness

  • Helpful
  • Neutral
  • Misleading
  • Obstructive
  • Hostile

Witness Accuracy

  • Accurate
  • Mostly Correct
  • Half Correct
  • Incorrect

Witness attributes provide an opportunity for skills use (Interviewing, Charm, Character Reading, etc.) to help the player evaluate whether the witness is accurate and helpful in continuing the investigation. Likewise, systems with PC reputation may adjust the witness attributes. Witnesses may need to be found and interviewed more than once: their statements may change (become more correct or change helpfulness) as the player obtains more clues or speaks to other witnesses.

Means depends on the crime committed and will need to be defined individually for each cause. For a death, means may be one of:

gun, knife, icepick, newspaper, pillow, animal, syringe, food, blanket, bag, telephone, wire, lighter

You should be able to pick out how some are appropriate or inappropriate for particular causes.

Time establishes when the action took place and may also impact the decay of clues or witnesses. Determining the time of the crime can be a reflection of the chosen difficulty of the system (cold cases are harder than recent murders).

Location establishes where (in which room) the action took place and can also impact the decay or spread of clues and witnesses. In a busy game, clues may be picked up by other players and moved from the room, or some clues attached to some objects may be obscured by later, replacement clues to more recent actions.

Putting it all together
To solve the mystery, the player will need to meet certain criteria:

  • obtain some percentage of the original clues (50% or more)
  • do not assign any incorrect clues to the mystery (the player should be able to deduce or discover this from in-game evidence or tools)
  • contacted and received statements from some percentage of the original witnesses (50% or more)
  • identified the victims of the mystery (100%)
  • correctly identified the actors (100%)
  • correctly eliminated innocent suspects (100%)

When the mystery is solved, the player can bundle up the results and turn it in for some reward. It’s up to the game system to determine how correct the player needs to be and what rewards are appropriate to that setting.

One Response to “It’s elementary”

  1. Mom Says:

    Great! Finally a role playing game that even I would be interested in playing.

    Is it possible to have a couple different player levels for this type of game? The elementary level would give feedback when collecting correct clues, interviewing witnesses, and assembling evidence. The advanced level wouldn’t provide as much assistance. Perhaps the advanced level would have a “clue/hint” option where a totally stymied player could click on “hint” for a little help.

    Let me know how this idea progresses. I love the concept.