Before we look at the design processes required to put a story into your game, you need to understand a number of key concepts, because they come up again and again throughout the discussion.
In the loosest definition, a story is an account of a series of events, either historical or fictitious. On that basis, a few people would say that every game contains a story because the action of the game can be described afterward. Although theoretically correct, this position isn't very useful to a game designer. The description of a Tetris game would be a supremely uninteresting story because of the game's endless repetition and its lack of emotional content, apart from the player's own feelings. It is so bad a story as to be not worth telling. If you're going to incorporate stories into games, they should be good stories.
For the purpose of putting good stories into games, we need to expand the original definition beyond "an account of a series of events." A minimally acceptable story, then, must be credible, coherent, and dramatically meaningful.
You can be the last member of the human race left alive, or you can invent a time machine, but not both.
—Ken Perlin, Professor at New York University
Credible simply means that people can believe the story, although in the case of fiction, they may have to suspend some disbelief to make belief possible. Many fantasy and science fiction stories incredible in real-world terms, become perfectly believable once the reader accepts their premises. Even fantasy and science fiction stories mustn't push it too far, as the quotation from Ken Perlin illustrates. They must also offer characters that the audience can sympathize with, identify with, or recognize as convincing. If a character isn't believable, the story is flawed. Humorous stories don't have to be as credible as serious ones. Different audiences also tolerate varying levels of credibility, so you should test your story on several people to see if they find it believable.
Coherent means that the events in a story must not be irrelevant or arbitrary but must harmonize to create a pleasing whole. Even if some events are not related by cause and effect or some events just add color, all events still have to belong in the story.
A story about the Apollo space program that included events from the first-century Roman invasion of Judea would be incoherent because the Roman invasion of Judea had no connection at all with the Apollo program. On the other hand, if the story of the Apollo program included a scene of Galileo building his telescope, that could be harmonious because Galileo's use of the telescope to study the heavens represents an important milestone in astronomy that ultimately led to the moon landings.
To be dramatically meaningful, the story's events have to involve something, or preferably someone, the listener cares about. The story must be constructed in such a way as to encourage the listener to take an interest in, and preferably identify with, one or more of the story's characters. When a game tells a story, the dramatically meaningful events may be explicitly planned by the writer, or they may arise naturally out of the process of playing. Either way, all events must contribute to the player's involvement in the story through identification with characters and interest in what happens to those characters. See the "Dramatic Tension and Gameplay Tension" section later in this chapter.
In English, stories—even those set in the future—are normally written using the past tense. An interactive story, on the other hand, takes place now, with the player in the middle of the series of events, moving forward through those events. Furthermore, the player's actions form part of the story itself, which makes an interactive story very different from a story presented to a passive audience. In fact, an interactive story includes three kinds of events:
■ Player events are actions performed directly by the player. In addition to giving the player actions to perform as part of gameplay—actions intended to overcome challenges—you can give the player additional actions to perform as part of the story. Role-playing by talking to other characters, for example, might serve the needs of the story even if overcoming the game's challenges does not require talking. If the player's actions can affect the plot of the story and change its future, they're called dramatic actions. Some player actions are not dramatic, however: Some player events aimed at overcoming challenges may not affect the plot.
■ In-game events are events initiated by the core mechanics of the game. These events may be responses to the player's actions (such as a trap that snaps when the player steps on a particular stone) or independent of the player's actions (such as a simulated guard character checking to see that the castle doors are locked). The player might be able to intentionally cause these events to occur, to change the way they occur, or to prevent them entirely—which is part of what makes the story interactive.
■ Narrative events are events whose content the player cannot change, although he may be able to change whether they occur or not. A narrative event narrates some action to the player; he does not interact with it. Narrative events are described in the "Narrative" section following this one.
With this in mind, consider the following formal definition of an interactive story.
INTERACTIVE STORY An interactive story is a story that the player interacts with by contributing actions to it. A story may be interactive even if the player's actions cannot change the direction of the plot.
This definition of an interactive story differs from those of many other designers, who often assert that if the player's actions do not change the direction of the plot (that is, the plot is linear) the story is not interactive. The power to change the direction of the plot—the story's future events—is called agency. Some designers feel that if a game with a story does not offer the player agency, it can't be said to be a truly interactive story. This is a misconception, because it ignores the role of the player's own actions in forming his experience of the game. A player still feels as if he is interacting with a story even if his actions do not change future events. The player contributes to the sequence of events, and that is what matters.
Consider a situation in which a player must find a way to get past a security guard to enter a building. You can give the player several ways to accomplish this: through violence, or trickery, or patience—waiting until the security guard goes off shift. No matter which approach the player chooses, he still enters the building through the same door and encounters the same things on the other side. If his decision does not actually affect the future events of the story, he has no agency. But his decision about how to get through the door contributes to the plot; his own actions are part of his experience of the game. This is how a story can be linear and still be interactive.
We discuss the distinction between stories that cannot be changed and those that can be changed in the sections "Linear Stories" and "Nonlinear Stories" later in this chapter.
Notice that the definition does not say anything about quality. Remember that to be a good story, a story's events must be credible, coherent, and dramatically meaningful. The player's actions constitute events in the story, so the more that those actions are credible, coherent, and dramatically meaningful events, the better the story will be. (Even an action that is not a dramatic action—one that changes the plot, as explained earlier—can still be dramatically meaningful; that is, it can be about something the player cares about.) When designing an interactive story, you shouldn't give the player things to do that don't credibly belong in the story; the result will be incoherent. In the Grand Theft Auto series, the player can't set up a charity for the homeless, and in the Police Quest series he can't steal cars.
In most games with an interactive story, the player's actions move the plot along. When the player overcomes a challenge, the game responds with the next event in the story. If the player doesn't overcome a challenge, either the story comes to a premature end (as it would when, say, the avatar dies in the attempt) or the story simply fails to advance—the player doesn't see future story events until he manages to get past the specific obstacle. However, there are exceptions to this arrangement; in some games the story progresses whether or not the player meets the game's
challenges. The section "Mechanisms for Advancing the Plot" addresses this issue in detail later.