Subplots vs Side Plots: What’s the Difference?

If you’ve ever stopped mid-draft and asked yourself: “Is this a subplot… or is it just a thing that happens?” You’re in good company.

Subplots and side plots are two of the most commonly confused elements in storytelling. Writers often use the terms interchangeably, assuming they serve the same purpose, or worse, add them without really knowing why they’re there at all.

The result? Stories that feel busy but shallow. Long but oddly unsatisfying. Full of interesting moments that don’t quite add up to something meaningful.

So, let’s slow things down and untangle the difference. This article will break down:

• A Quick Foundation: What Is the Main Plot?
• What Is a Subplot?
• Examples of Subplots (In Practice)
• What Is a Side Plot?
• Examples of Side Plots
• The Crucial Difference: Impact
• Why This Distinction Matters
• Can a Side Plot Become a Subplot?
• How Many Subplots Should a Story Have?
• Bringing It All Together
• Get Sketches & Storytelling Delivered to Your Inbox.

No academic jargon. No recycled definitions. Just clear, practical storytelling guidance.

---

A Quick Foundation: What Is the Main Plot?

Before we talk about subplots and side plots, we need a shared anchor point.

As outlined in my guide to plot patterns, the main plot is the core narrative engine of your story – the sequence of cause-and-effect events centred on your protagonist’s primary goal and the central conflict standing in their way.

In simple terms, the main plot answers this question:

What is this story about, and what must change for it to end?

If you remove the main plot, there is no story, only fragments. 

The only benefit of this would be having the ability to find a recipe online that doesn’t go on a 1200-word ramble about Aunt Enid’s first foray into the French Riviera, where she decided to begin the family cookbook that was passed down to the food blogger you’re currently reading… I digress.

Subplots and side plots don’t exist independently. They only make sense in relation to this central spine.

---

What Is a Subplot?

A subplot is a secondary narrative thread that runs alongside the main plot and directly supports it.

It doesn’t replace the main plot, compete with it, or distract from it. Instead, it deepens the story by exploring complementary emotional, thematic, or relational terrain.

A subplot reinforces the main plot by developing character, theme, or stakes in a way the main plot alone cannot. 

Subplots add meaning, not just movement.

---

What Subplots Actually Do

A well-crafted subplot typically serves one or more of the following purposes:

• It reveals a different side of the protagonist
• It mirrors or contrasts the central conflict
• It raises emotional stakes
• It explores the Story Keystone from another angle
• It forces the protagonist into harder choices
  

Crucially, a subplot intersects with the main plot. It may collide with it, complicate it, or quietly reshape how it resolves, but it’s never isolated from it.

Structure of a Subplot

Subplots aren’t random. They have shape and substance. Like the main plot, a subplot usually has:

• A beginning (introduction of the secondary conflict or relationship)
• A development phase (tension, growth, complication)
• A resolution (which often feeds back into the main plot)
  

The difference is scale. A subplot may be smaller, tighter, and more focused, but it must still be complete.

If you removed a subplot, your story would still function, but it would feel thinner, flatter, or emotionally weaker.

---

Examples of Subplots (In Practice)

Let’s ground this with a few familiar examples.

Internal Character Subplots

These track a character’s emotional or psychological journey alongside the external plot.

In The Lion King, Simba’s external goal is reclaiming Pride Rock. His internal subplot – grappling with guilt, shame, and identity – is what makes that goal meaningful. The story can’t resolve until both threads are complete.

Relationship Subplots

Romantic, familial, or friendship arcs often operate as subplots.

In The Lord of the Rings, Sam’s loyalty to Frodo isn’t just emotional decoration. It directly enables the quest to succeed. Remove that subplot, and the main plot collapses – a bit like Frodo on Mount Doom…

Secondary Character Growth

A supporting character’s arc can function as a subplot that reinforces theme.

In The Dark Knight, Harvey Dent’s descent operates as a subplot alongside Batman’s central struggle. Dent’s transformation into Two-Face mirrors the film’s exploration of chaos, moral compromise, and the fragility of idealism. His arc doesn’t replace the main plot, but it deepens its stakes and crystallises its themes, showing what happens when hope is corrupted rather than upheld.

---

What Is a Side Plot?

A subplot is a narrative thread that exists alongside the main plot but doesn’t meaningfully impact its outcome – this is the key distinction.

A side plot adds texture to a story without altering its core trajectory. They can be entertaining, enriching, and even beloved, but they’re not structurally essential.

What Side Plots Are For

Side plots typically exist to:

• Add worldbuilding detail
• Provide tonal contrast or comic relief
• Explore minor characters
• Offer breathing room between major story beats
  

They enhance immersion, but they don’t drive the engine. If you removed a side plot, the main story would still stand largely unchanged. They also often act as a procrastinative distraction from your story.

Structure of a Side Plot

Side plots are often:

• Shorter
• Episodic
• Self-contained
• Loosely connected (if at all) to the central conflict
  

They may start and end without intersecting the main plot in any meaningful way, and that’s fine, as long as it’s intentional.

---

Examples of Side Plots

Comic or Tonal Side Plots

Many stories include lighter threads that exist primarily to shift tone, provide relief, or deepen the emotional texture of the world rather than advance the central narrative.

Fred and George Weasley’s escapades throughout the Harry Potter series are a strong example. Their pranks, jokes, and entrepreneurial mischief inject humour into an otherwise darkening story, offering moments of levity and rebellion that make the Wizarding World feel alive and human.

But structurally, these moments don’t alter the story’s direction. Voldemort’s  (oops, I named him…) rise is unaffected. Harry’s choices remain unchanged. The core conflict marches on regardless of whether a corridor explodes with fireworks or a professor is publicly humiliated.

Remove these moments, and the plot still functions. What’s lost isn’t momentum or meaning – it’s texture. That’s the hallmark of a tonal side plot: memorable, enriching, and emotionally valuable, yet narratively optional.

Worldbuilding Detours

Festivals, travel episodes, cultural rituals, or minor conflicts that exist primarily to show the world. They help the setting feel lived-in, but they don’t change the story’s destination.

The Mos Eisley cantina scene is iconic – and almost entirely a detour for worldbuilding. It introduces alien diversity and establishes tone and moral greyness whilst signalling that this is a wider, stranger galaxy than we may have thought.

But beyond the brief introduction of Han Solo (which could be achieved elsewhere), the sequence itself doesn’t change the plot’s direction. Luke still leaves Tatooine. The Death Star still exists. The rebellion still needs help.

It enriches the world without affecting or steering the story.

Minor Character Moments

A short arc involving a side character that never meaningfully impacts the protagonist’s journey.

Enjoyable? Absolutely. Essential? No.

Barliman Butterbur, the innkeeper at The Prancing Pony, is a great example in The Fellowship of the Ring. He provides flavour and humour as he briefly interacts with the protagonists, but he doesn’t alter Frodo’s choice or affect the Ring’s journey.

The plot moves forward with or without him. He enriches the world, but he doesn’t steer the story.

---

The Crucial Difference: Impact

Here’s the simplest way to tell subplots and side plots apart:

Ask yourself:

• Does this thread change the protagonist?
• Does it affect the main conflict?
• Does it influence the resolution?
  

If the answer is yes, you’re dealing with a subplot.

If the answer is no, it’s a side plot.

Neither is inherently better; they both have their place. Problems only arise when writers think they’re writing subplots but are actually stacking side plots instead.

---

Why This Distinction Matters

When subplots and side plots are confused, stories suffer in subtle but significant ways.

Common symptoms include:

• Meandering narratives
• Strong scenes with no cumulative payoff
• Overdeveloped worlds with underdeveloped characters
• Stories that feel long but emotionally hollow
  

Understanding the difference helps you make conscious structural choices rather than piling on material and hoping it works itself out.

---

Can a Side Plot Become a Subplot?

Yes, and this often happens organically during drafting.

A side plot becomes a subplot when:

• It begins to affect the protagonist’s decisions
• It reinforces the story’s core theme
• It meaningfully intersects with the main conflict
  

This isn’t a mistake. It’s often a sign that the story is discovering what actually matters. The key is awareness. If a side plot starts demanding narrative weight, decide whether you’re willing to let it earn that place and stick with your decision. 

---

How Many Subplots Should a Story Have?

There’s no universal number, but there is a principle:

Every subplot must justify its existence.

Short stories often have none. Novels may have one to three strong subplots. Epic or ensemble stories can support more, but only with careful balance.

If a subplot doesn’t deepen character, theme, or stakes, it’s probably not a subplot at all.

---

Bringing It All Together

Your main plot is the road. Subplots are the companions who change the journey. Side plots are the scenery along the way.

Mistake one for the other, and your story may still move, but it won’t arrive with impact.

Subplots add meaning. Side plots add texture. Both have their place, as long as you know which is which.

Readers don’t remember how many threads your story contained. They remember whether it felt focused, purposeful, and emotionally true.

And that clarity starts with understanding what each narrative thread is actually doing.