Is the middle of your story feeling a little flat? Are you struggling to show your protagonist’s true humanity? Maybe you’re trying to discover your character’s need? It sounds like you could do with a subplot.

Whether you’re writing a play, a novel, or a screenplay, we all reach a point in the story where the energy of the opening slumps and we lose sight of the emotional truth of the character’s journey.

In this article, we’ll look at how subplots function across the three acts and how they ignite the Rising Action and pay off in the Falling Action. And we’ll explore how Kelley and Wallace used subplot in the 1985 film Witness.

Ready? Let’s go!

What is a subplot?

In strong narrative design, a subplot (a.k.a sub-ordinate plot) isn’t just a secondary storyline running parallel to the main action.

It’s a deliberate pressure point—a situation, relationship, or conflict that couldn’t sustain a story on its own. However, it becomes indispensable because it reveals an aspect of the protagonist that the main plot cannot reveal.

A subplot is not a distraction. It shows us who the protagonist is when the story’s central engine isn’t looking.

Subplot is structural

Subplot is one of the most misunderstood tools in narrative craft. In strong storytelling — especially within the three‑act structure — a subplot is:

• Structural
• Psychological, and 
• Revelatory.

A subplot is the narrative corridor through which the audience glimpses the protagonist’s emotional need.

It reveals their hidden contradictions, their unspoken desires, or the part of their humanity that the main plot — often too urgent, too dangerous, too procedural — cannot access.

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The Function of Subplot

A well‑built subplot typically does three things:

1. It exposes a facet of the protagonist that the main plot can’t reach.

The main plot is often too busy with external stakes, procedural momentum, or survival pressure to allow the protagonist to reveal their emotional, moral, or relational depth. The subplot opens a side door.

2. It creates contrast.

By placing the protagonist in a different emotional or cultural environment, the subplot reframes them. We see them under a different light, and the contrast sharpens our understanding.

3. It pays off in the Falling Action.

A subplot often resolves after the mid-point climax at the end of the Rising Action.

This is where the protagonist has achieved the thing they thought would solve the Problem of the World. But it doesn’t.

The subplot drives us into the Falling action, allowing the protagonist’s internal shift to land. It’s where the story’s emotional consequences crystallise.

Is it just a B-Story?

TV soaps often carry several storyline threads in a single episode. There’s the principal thread of action (the A-story), which is typically interspersed between other stories that run alongside it (the B, C, and D stories).

But, essentially, the B, C, and D stories aren’t subplots. In soap, those stories run alongside each other. Sometimes they cross paths, but they’re really there for contrast and texture—a way to follow multiple characters.

But the subplot isn’t external to the story’s world in the 3-act structure. It runs alongside the principal plot and pays off later.

What a Subplot Actually Is

The principal plot is usually driven by external stakes: survival, justice, escape, victory, exposure, pursuit. It is the engine that propels the story forward.

The subplot, by contrast, is driven by internal stakes: longing, vulnerability, emotional need, moral conflict, desire, shame, fear of intimacy, fear of failure.

The subplot is where the protagonist’s emotional arc lives.

Why the Subplot Cannot Stand Alone

A subplot is not a “mini‑plot.” It is not a B‑movie tucked inside an A‑movie. It is not a diluted version of the main story.

A subplot cannot stand alone because:

• It lacks the structural force to carry a full narrative.
• It depends on the main plot to give it context, pressure, and meaning.
• It is designed to illuminate the protagonist, not to replace them.

If you removed the subplot, the main plot would still function — but the protagonist would be emotionally flatter, less dimensional, and less human.

If you removed the main plot, the subplot would collapse. It is parasitic by design — but in the best possible way.

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The Subplot’s Role in the Three‑Act Structure

Across the three‑act structure, the subplot has a very specific rhythm.

We’ll explore this through the prism of Witness (1985), starring Harrison Ford and Kelly McGillis, which won the Academy Award for Best Original Screenplay in 1986.

Act I: The Setup — The Subplot Is Seeded

The subplot is rarely active in Act I. Instead, it is introduced or foreshadowed. We glimpse the person, situation, or emotional pressure that will later become the subplot.

In Witness, Rachel Lapp and her son Samuel are introduced early, but the subplot does not ignite yet. The story remains within the principal plot: the murder, the investigation, the conspiracy.

The Rising Action — The Subplot Ignites

The Rising Action of Act 2 is where the subplot comes alive.

This is because:

• The protagonist is now under sustained pressure.
• The main plot has destabilised their world.
• They are forced into new environments, relationships, or moral dilemmas.

The subplot typically ignites early in the Rising Action, often shortly after the First Plot Point, when the protagonist is thrust into a new situation.

In Witness, the subplot ignites when John Book (Harrison Ford) and the Amish family retreat to the Amish community for safety. This shift in environment creates the conditions for the subplot — the emotional and relational storyline — to begin.

The Falling Action — The Subplot Pays Off

The Falling Action of Act 2 is where the subplot finally pays off.

This is because:

• The protagonist has survived the initial conflict, but it didn’t solve the problem.
• The revelation that they haven’t won hits hard, and it drives them towards a new internal crisis.
• The emotional truth of the protagonist’s journey must land.

The subplot’s payoff is often the emotional zenith that gives the story its final resonance.

In Witness, everything Book has learned and built in the Amish world is threatened. He realises he cares for Rachel and Samuel, but he recognises that keeping them safe is going to cost him dearly.

Act III — Facing the Problem of the World

By Act III, the subplot has done most of its work, but it’s what brings clarity to the final confrontations that must take place in Act 3.

The protagonist faces the Problem of the World with a fuller understanding of themselves, thanks largely to the subplot. The emotional truth revealed by the subplot gives the final confrontation its weight.

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How Subplot Adds Dramatic and Emotional Texture

A well‑designed subplot typically performs several functions:

1. Emotional Revelation

It shows the protagonist’s vulnerability, desire, or longing — the part of them the main plot cannot reach.

2. Contrast and Reframing

It places the protagonist in a different environment or relationship, allowing us to see them under a new light.

3. Deepening Stakes

It gives the protagonist something personal to lose, beyond the external stakes of the principal plot.

4. Thematic Echo

It mirrors or challenges the themes of the main plot, often in a more intimate register.

5. Falling‑Action Payoff

It intensifies the emotional cost of the “all is lost” moment, making the low point not just situational but deeply personal.

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Case Study: Witness (1985)

Witness is a masterclass in subplot design. Without the subplot, the film would be a competent thriller. With it, the story becomes a meditation on belonging, gentleness, and the cost of connection.

The Principal Plot

Detective John Book (Harrison Ford) is assigned to investigate the murder of an undercover police officer. When the young Amish boy Samuel identifies a high‑ranking officer as the killer, Book realises the conspiracy reaches deep into the police force. After being attacked, he flees with Samuel and his mother, Rachel, to the Amish community to keep them safe.

This plot is procedural, dangerous, and externally driven. It cannot reveal Book’s emotional life.

The Subplot: John Book and Rachel Lapp

Rachel Lapp (Kelly McGillis) is not simply a love interest. She is the subplot — the narrative space where Book’s emotional need is revealed.

When Book hides in the Amish community, the subplot ignites. Removed from his violent, cynical world, he is placed inside a culture defined by pacifism, community, and simplicity. This environment exposes a different side of him:

• his gentleness,
• his capacity for affection,
• his longing for connection,
• his conflict between two incompatible worlds.

This storyline would not carry a full film on its own. But as a subplot, it is indispensable.

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Mapping the Subplot onto the Three‑Act Structure

Act I — The Setup

• Samuel and Rachel are introduced.
• Samuel witnesses the murder.
• Book begins the investigation.
• The conspiracy is hinted at.

The seeds of the subplot are present, but it is not yet active.

Act II (first half) — The Rising Action: The Subplot Ignites

Book’s Rising‑Action Objective

To keep Samuel and Rachel safe while staying alive long enough to expose the conspiracy.

This want drives every action he takes.

How He Pursues It

• He removes the witnesses from danger.
• He hides in the Amish community.
• He recovers from his injuries.
• He blends into Amish life to avoid detection.
• He maintains the investigation from a distance.
• He protects the community from the violence he brings with him.

Where the Subplot Ignites

As Book integrates into Amish life:

• he works alongside the community,
• he forms a bond with Samuel,
• he and Rachel develop mutual affection,
• the community reacts with suspicion, curiosity, or disapproval.

The Rising Action now carries two tracks:

• the external pressure of the conspiracy, and
• the emotional pressure of the subplot.

Act II (second half) — The Falling Action: The Subplot Pays Off

The Falling Action is where everything begins to unravel.

Principal Plot Pressure

• The corrupt officers close in.
• Book’s presence threatens the community.
• Violence looms over a pacifist world.

Subplot Pressure

• Rachel’s feelings for Book become more visible.
• Her father‑in‑law warns her about the consequences.
• Book realises he cannot belong in this world.
• The emotional stakes peak.

The “All Is Lost” Moment

Book understands:

• he loves Rachel,
• he cannot stay,
• his presence endangers everything she holds dear.

The Problem of the World — corruption, violence, the system Book comes from — appears to have won. The subplot delivers the emotional collapse that defines the Falling Action.

Act III — Facing the Problem of the World

The corrupt officers arrive at the farm. Book confronts them, using his skills and the environment to expose the conspiracy publicly. He protects the community, but at a cost.

After the confrontation, Book and Rachel face the truth:

• their worlds are incompatible,
• their connection cannot survive,
• he must leave.

The subplot has already done its work. Act III is the reckoning.

Why Subplots Matter

As we’ve explored, the subplot is not just a secondary story; it’s the emotional architecture of the narrative.

• The principal plot shows what the protagonist does.
• The subplot shows who the protagonist is.

Placed correctly within the three‑act structure:

• it ignites in the Rising Action,
• pays off in the Falling Action,
• and gives Act III its emotional weight.

Without the subplot, Witness would be a thriller. With it, the film becomes a story about longing, belonging, and the cost of connection.

That is the power of a subplot: it helps the theme emerge.

How to Incorporate all This into Your Next Story

The theory is one thing, but applying it can feel intimidating.

That’s why we set up our new Top of the Stack: Act 2 course, to help writers navigate their way through the complex second act.

Through taught sessions, discussions, exercises, and sharings, we help writers to find the answers that satisfy the story they’re looking to tell.

Join the Top of the Stack

Our new courses are designed to help playwrights of all experience levels create an opening that catches readers’ attention (Top of the Stack: the First 10 Pages) and sustain that energy through the tricky middle (Top of the Stack: Act 2).

Soon to come will be Top of the Stack: Act 3, so if you’re struggling to find an ending, this could be precisely what you need.

Or listen to the WriteForTheStage Podcast episodes that break down the 3-act structure into easy-to-digest sections.

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