Reusable plots for quests

[Brian Price]

Three or four years ago, I was working on a multi-plot interactive 
story/game.  While I never finished it, I did lay out the groundwork 
for such a system.  Some of the recent topics touched upon the desire 
to provide re-usable quests and those discussions reminded me of my 
earlier work.  Please bear with me, it is a bit rough and a bit long 
winded.

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The dynamic plot element node logic theorem
January 14, 1994
by Brian L. Price

A story can be expressed as a combination of three plot scopes;  the
master plot, the sub-plot, and the random event (or micro-plot).  A
master plot consists of a dozen or more significant scenes spread, on
average, widely through the story's time and space.   Generally, the
master plot begins near the beginning of the story and continues
through to the end.  The master plot is the main story line.  

The main difference between a synopsis and an actual story is that the
synopsis covers only the most significant portions of the story, in
other words, the master plot.  Thus it can be stated unequivocally
that a story consists of more than the master plot.  One of these
other ingredients is the sub-plot.  A sub-plot is a short story
interwoven within the confines of the master plot.  Although most
sub-plots are related to the main plot, the relevence of the sub-plots
vary even within the same story.  A sub-plot typically consists of
less than half a dozen or so significant scenes and is expressed in a
time and space scope significantly smaller than the master plot.  

One difference between a novella and a novel is the drastic reduction
with the novella form in the number of seemingly inconsequential
events interspersed throughout main and sub-plot alike.  These events
can be described as random events or micro-plots.  These micro-plots
typically have a scope of only a single scene and have only minor
relevance to any sub-plot or master plot serving mainly to add color
although occasionally affecting plot direction.

A reoccurring component of master plot, sub-plot, and micro-plot alike
is the concept of a scene.  A scene can be expressed as a story node,
and a story can be viewed as a sequence of interconnected nodes. 
Furthermore, these nodes can be subdivided as to ownership by master
plot, sub-plot, or micro-plot.  Each scene, or node, is composed of a
collection of elements.  Not all scenes possess all elements, but all
scenes are expressible as a subset of a common set of plot elements.

A somewhat arbitrary choice of basic plot elements can be made to form
the common set of plot elements.  The current plot element node logic
theorem holds that these elements can be defined as setting,
character, information, features, and events.  The element setting can
be described as the physical surroundings in which the scene occurs. 
The character element consists of the characters and creatures which
are within the setting during the time the scene occurs.  The
information element consists of knowledge which may be obtained by or
imparted to a character from some other element during the course of
the scene.  

Features are generally immovable physical objects within the setting
which have some special significance to the plot and which may be
accessed and/or activated during the course of the scene.  Events
cover  a wide range of elements which may exist or occur within the
scene and perhaps beyond but which are usually beyond the control of
any of the characters, this covers elements such as weather, war,
natural disaster, etc.  Of course, the scene would not be complete
without resolution, that is, the interaction between the various
elements during the time frame of the scene.  

Given that: 
a)  Any scene can be described in terms of a subset of the set of
     plot elements together with the interaction between them.
b) Any plot can be described as a sequence of scenes, 
c) Any story can be described as a collection of plots.
Then  any static story can be completely described using plot element
node syntax.

Assuming this to be true, a dynamic story, that is one where the
various plots have multiple possible paths, could also be described
using plot element node syntax if, and only if, a system of logic was
developed that could express the relationships between the plot nodes
in a non-deterministic form.  That is to say, a system of logic which
could resolve the various scopes, probabilities, exclusions, and
dependancies between various plot element nodes in such a way as to
allow character action and story universe mechanics to determine the
plot path, and thus the story's evolving reality.

In a dynamic story, each plot node (or scene) has a number of defining
states or boundary conditions.  A plot node has a region of space in
which it can occur, a frame of time in which it may occur, a
probability of occurance, a uniqueness factor, and an existance
factor.  A unique node may only appear at most once in a story.  An
existant node's setting and possibly its feature(s) or characters may
be revisited.  Existant node events which are of a persistant and
regional or global effect will alter the reality state of the story
universe for their duration.  

Still, in order to form plots, relationships between plot nodes must
be defined.  The primary relationships are: exclusion, dependance,
time frame accleration, time frame deceleration, probability increase,
and probability decrease.   That is, the transition from non-existant
to existant of one plot node will: cause the removal of all plot nodes
which are related to it by exclusion, the existance of all dependant
plot nodes, a time frame shift toward or away from the present for all
plot nodes related through time frame acceleration or deceleration,
and the alteration of the probability for future existance of all plot
nodes related by probability increase or decrease.

The primary mechanism for bringing a plot node into existance is that
of main character action and present plot node resolution.  All plot
elements except setting can possibly trigger the existance of a plot
node or alter plot node boundary conditions.  A plot thread is defined
by the set of possible existance triggers and dependancies within the
starting plot node and possibly at each subsequent plot node within a
main or sub plot.  These triggers can be represented by a change in
plot element condition, ie the death of a character, the gaining of
information, the activation of a feature, etc.

Plots become defined as their starting nodes come into existance and,
one by one, all but one reality thread eliminated.  (A reality thread
being a sequence of plot nodes.)  The relationship mechanism described
herein automatically allows for maintenance of story integrity and
proper interaction between main, sub, and micro plots.  Application of
this theorem to computer games should provide sufficient dynamic plot
complexity so as to prevent most players from guessing the game future
even after many replays.  
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The main stumbling block I ran into when attempting to implement the 
above was in what we would call for muds the builder interface.  I 
never did come up with a good way to make designing multi-plot 
stories easy.  I hope this sparks some thought, perhaps one of you 
can pick up where I left off and turn the above into a workable 
system.

Brian Price