Like a key in a lock, each narrative element must perfectly adapt to the context of the story to move it forward. A new character, setting, or prop possesses characteristics that must fit into the existing narrative to create fluid and credible movement.
The Key and Lock Metaphor
The functioning of a lock with its key is absolutely obvious to everyone. An ill-fitted key will not be able to open the lock. However, a relatively similar key, with some forcing, might manage to open the lock. And someone with the technique to pick locks might succeed in opening it without a key.
This metaphor seems very useful when applied to screenwriting, to the narrative elements that build a story and move it forward. Let’s consider a new narrative element – a character, a setting, a time of day, a prop, etc. Let’s view it as a key, with the general context of the story being the lock. If this key adapts to the general context, it will unlock the lock, that is, move the story forward.
Narrative Thresholds
A key consists of a number of notches and bumps that correspond, in negative, to the constituent elements of the lock. Thus, if we take the example of a new character entering the story, they must have a certain number of characteristics that will fit into the constituent elements of the pre-existing narrative: their relationship with other characters, their place in the social context, their position in the family being discovered, etc. Of course, this new character also has their own personality and specificities, with which they can enrich the story.
But in my opinion, we should never forget to consider them as a key entering the context of the story. Thus, we can anticipate how, once all the narrative elements of this character align with the whole story – like a key that will perfectly insert into a lock – this will, at some point, move the story in a major way, making it cross a threshold in the narrative. This is built through an addition of small elements, like the notches and bumps of the key, which, once aligned, allow the story to progress in a powerful, fluid, and plausible manner.