A story arc (also known as a narrative arc) is the chronological construction of a plot in a novel, or story. It can also mean an extended, or continuing storyline in episodic storytelling media such as television, comic books, comic strips, video games, and movies with each episode following a dramatic arc.

The first part of constructing a plot arc for your storyline is to ask the ‘5 W’s’ –

• Who
• What
• Why
• Where
• When

These will give you a starting point to how your narrative will commence and how the story will be shaped as you write your characters lives.

Let’s look at an example of a plot arc. As we all know a book, or indeed a movie, has a main protagonist, but there are also sub story lines. For example, we can use a superhero movie. There is the main arc, which is main focus of the story—a superhero who saves the world, but there are subplots, each with their own arc. We have the villain, the sidekicks, the general ‘public’ etc.

There are seven types of characters in stories and literature.

• Protagonist - the leading character.
• Antagonist - a person who actively opposes, or is hostile to the protagonist, an adversary.
• Deuteragonist - the second character in importance to the protagonist in a story. Sidekick, best friend etc.
• Tertiary Characters - the third most important characters.  They often only pop up in a scene or two, perform a plot-relevant function, and then leave for good.
• Romantic Interest.
• Confidant. A person with whom a secret or private matter is shared. This can be a friend, or foe depending on your narrative.
• Foil - someone that makes another's character’s good or bad qualities more noticeable.

A traditional narrative arc has five elements, in the following order:

1. Exposition. Introduction to the story. 
2. Rising action. When the conflict begins to ramp up.
3. Climax. The point in the narrative where the tension, excitement, or stakes reach the highest level.
4. Falling action. The action that occurs immediately after the big climax has taken place and the action shifts towards resolution instead of escalation.
5. Resolution. The conclusion of the story by the resolving of conflicts between characters.
6. These elements can be further broken down into eight points: stasis, trigger, quest, surprise, choice, climax, reversal, and resolution.

There are also six archetypal plot arcs.

These narrative arcs are called ‘archetypal’ because they are the common patterns that countless stories follow, albeit with variations.

1. Rags to Riches [a complete rise]

2. Riches to Rags [a fall]

3. Man in a Hole [fall then rise]

4. Icarus [rise then fall]

5. Cinderella [rise then fall then rise]

6. Oedipus [fall then rise then fall]

So how do we write a character arc?

1. First Act — how your character starts, in some ways, this is the prologue work.
2. Second Act — how your character develops.
3. Third Act — how your character ends up. Make sure your story’s middle fluctuates more to sustain interest.
4. Add conflicts – internal and external.
5. Remember the three C's of a basic story arc - the conflict, the characters and the climax.

Instead of totally focusing on the main characters, create several lesser arcs within your primary plot arc. After all, your main characters are not living in a self-contained world. This method has multiple benefits:

• You have other sources of tension and narrative interest during stretches of your story where primary conflicts move to the background. This maintains story momentum.
• Your smaller arcs give you means to develop your characters and tease out central themes. For example, Harry Potter’s primary conflict is with the main villain, Voldemort, but there are many other substories throughout the series.
• Smaller arcs supply additional stakes, adding tension. For example, secondary relationships form over the course of Harry Potter and give him more to lose as the threatening villain grows more powerful.
• All stories fall into six emotional arcs—or, rather, three arcs and their inverses.

A handy way to assist you maintain your story arc is to make visual diagrams, like the ones below. Mapping out your story can help you stay on track, but remember slight diversions make the process more fun! Sometimes secondary characters can become key to the narrative and give more depth to your story.