Is It a Mystery or Is It a Thriller?

By Michelle Barker and David Griffin Brown

What is the difference between mystery and thriller?

If you’ve ever been stymied by that question, you’re not alone. The difference between mysteries and thrillers can be tricky to spot, and there can be a lot of overlap between the genres. Throw in suspense and adventure and you’ve got yourself a genre soup.

A useful way to think about the distinction is this: mysteries look backward, while thrillers look forward.

In other words, a mystery is about trying to figure out what happened in the past. A thriller is about trying to stop something bad from happening in the future.

Of course, the two frequently overlap. Mysteries often include moments of danger and suspense. Thrillers often include some mystery about what the antagonist is planning or why. And some stories genuinely sit in both camps.

A quick example shows how the same premise can shift genres depending on where the narrative pressure lies.

Mystery version

• A woman is found dead in a locked room.
• A detective studies clues and interviews suspects.
• The climax reveals who committed the murder.

Thriller version

• A killer leaves locked-room murders as a signature.
• An investigator realizes another victim will die soon.
• The climax stops the next murder.
  

Same ingredients, different narrative engine.

Mysteries: Probing a Pernicious Past

A mystery will feature a detective in some form, whether it’s a private investigator, a police officer, or an amateur sleuth. There is often a structural plot point early in the novel to give the reader an indication of how the protagonist thinks or what their moral code is—sort of like an intellectual or moral flex that says I’m the right person for this job and here’s why.

The plot of a mystery focusses on solving a puzzle, and the key question will either be whodunit? or whydunit? (or both). The emphasis is on the intellectual challenge of solving the puzzle and involves looking backward and trying to figure out how the bad thing happened.

Because an investigation tends to be systematic, the plot is usually structured linearly as clues come up and suspects are introduced. In the climax, the mystery is solved and the truth is revealed.

Examples include the classic mysteries by Agatha Christie (Murder on the Orient Express) and Arthur Conan Doyle (The Hound of the Baskervilles).

That said…

Many mysteries involve the detective or amateur sleuth getting themselves into trouble, especially near the end. In Postmortem, Kay Scarpetta nearly becomes the killer’s next victim, as does Kinsey Millhone in A Is for Alibi.

Thrillers: Fighting a Fatal Future

Thrillers prioritize tension, suspense, and excitement. They often involve life-threatening situations and danger, and the main goal is the prevention of disaster.

While a mystery is primarily about looking backward, the central question in a thriller is: what will happen next?

Thrillers tend to be faster paced than mysteries, aiming to keep readers on the edge of their seats with high-octane action. Think of Jack Reacher uncovering a conspiracy while powerful enemies close in on him in Lee Child’s Killing Floor, or Clarice Starling racing to save a kidnapped victim before a serial killer strikes again in Thomas Harris’s The Silence of the Lambs. Readers can expect a constant ratcheting up of stakes—one ticking clock after the next. (A ticking clock in a mystery tends to pressurize thinking, whereas in a thriller it pressurizes action.)A thriller will often also include the antagonist’s point of view (another tactic to amplify the stakes).

In The Da Vinci Code by Dan Brown, Robert Langdon and Sophie Neveu are constantly on the run while trying to decipher clues that lead to a secret that powerful forces want to control. The suspense comes from the escalating danger as they try to uncover the truth before their pursuers catch them.

In The Firm by John Grisham, Mitch McDeere slowly realizes the law firm he joined is tied to organized crime. The tension comes from what will happen if the firm realizes he knows too much—and whether he can escape before they eliminate him.

But how do these stories differ from a typical adventure novel?

Both use a similar structure that relies on escalation, reaction, and survival. Things just keep getting worse. The protagonist trying to stop a terrorist is not all that different from Frodo trying to stop Sauron, yet no one would call The Lord of the Rings a thriller. It might have the suspense and action of a thriller, but it’s missing the principal feature of real-world (and often contemporary) crime.

When a Story Employs Mystery Without Being a Mystery

To complicate matters further, many novels include an element of mystery in the plot or even in the protagonist’s backstory but are not classified as mysteries because they don’t follow the typical mystery structure.

In these cases, the mystery creates tension, but the story isn’t primarily about solving a puzzle.

Take Gone Girl. Amy Dunne disappears, and the novel initially resembles a crime investigation. But the real focus of the story is the toxic dynamic between Amy and her husband Nick. The mystery drives the drama, yet the novel functions more as a psychological suspense about manipulation and revenge than as a traditional mystery.

Something similar happens in Everything I Never Told You by Celeste Ng. Lydia Lee’s death forms the central mystery of the novel, and the characters desperately want to know what happened. But the story is really about the Lee family—their expectations, misunderstandings, and grief. The mystery reveals emotional truths about the family rather than serving as the central investigative engine. So in this case, we have a family drama as the narrative engine.

In both cases, the mystery is present, but the story isn’t structured around an investigator systematically solving a puzzle.

Hybrids: When a Story Does Both

A mystery can take on thriller vibes when the detective becomes the next target. While the focus is on solving the mystery, the story may also include action sequences, chase scenes, and intense confrontations.

On the flipside, a thriller might contain a mystery about why the antagonist is doing what they’re doing, or the protagonist may need to solve small mysteries along the way to prevent a future calamity.

Some novels genuinely combine both engines.

Postmortem

Patricia Cornwell’s Postmortem, in which a serial killer needs to be stopped before they strike again, is a good example of a novel that has a foot in each camp.

The stakes are high: forensic pathologist Kay Scarpetta faces significant danger as she works to track down the killer, and in the process becomes a target herself.

The plot includes a ticking clock—the serial killer who’s still at large. There is clear and present danger as the story proceeds.

However, the novel is structurally anchored in forensic investigation rather than pursuit. We spend a significant amount of time watching Scarpetta conduct autopsies, analyze the findings, reconstruct the crime and piece it together based on the evidence.

Even when there is danger, the primary movement in the narrative is from ignorance to understanding, which lands it more firmly in the mystery genre.

More firmly—but not completely.

A subplot creates numerous red herrings that make it seem like the killer is purposely obstructing Scarpetta’s investigation. That gives it undeniable thriller vibes, but in fact this is related to police politics. Homicide investigator Pete Marino has to rescue Scarpetta when she’s attacked by the killer. More thriller vibes, since this involves guessing where the killer will strike and then outmaneuvering him.

But because Scarpetta isn’t being hunted all the way through and the novel focusses mostly on evaluating and understanding evidence, it doesn’t fully wander into thriller territory.

Magpie Murders

Anthony Horowitz’s novel Magpie Murders employs elements of both mystery and thriller in an unusual way because there are two stories going on at the same time: Alan Conway’s novel, which is a mystery, and his murder.

Even though there is some suggestion in Conway’s novel that the killer might strike again, it feels unlikely; whereas Susan Ryeland, Conway’s editor and the protagonist who is trying to solve his murder, actually is under threat herself. The murderer is still at large, we don’t know who it is, and they are actively trying to stop her from discovering the truth.

Horowitz purposely plays up this contrast between the classic mystery puzzle and the ticking clock of a thriller, since part of what he’s doing is metafictional. He’s commenting on the nature of the mystery genre itself. He uses the mystery in Conway’s novel to fuel the ongoing threat to Ryeland after Conway himself is murdered. From then on, Ryeland’s inquiries are no longer academic. The more clues she uncovers, the greater the danger she’s in.

The focus stops being what happened? and becomes what will happen next if she keeps pursuing this?

In Conclusion

Knowing which genre you’re writing in helps determine where the main tension should be and what kind of suspense dominates the narrative. Here’s a checklist that might help.

You’ve probably written a mystery if…

• the primary focus of the novel is to figure out something that happened in the past
• the antagonist remains hidden from the reader
• the reader is also trying to solve a puzzle
• the stakes are more intellectual
• the key question is: “Who did it and why?”
• the scenes advance by discovery
• the danger comes from being wrong

You’ve probably written a thriller if…

• the conflict involves an ongoing threat that must somehow be stopped
• the antagonist is a clear and present danger
• the reader is desperate for the protagonist to put an end to the threat
• the stakes are more emotional
• the key question is: “How do we stop this?”
• the scenes advance by confrontation
• the danger comes from failure
  

Michelle Barker is an award-winning author and poet. She is the co-author of two craft books: Immersion and Emotion: The Two Pillars of Storytelling and Story Skeleton: The Classics. Her fiction, non-fiction, and poetry have appeared in literary reviews worldwide. She has published three YA novels (one fantasy and two historical fiction), a historical picture book, and a chapbook of poetry. Michelle holds a BA in English literature (UBC) and an MFA in creative writing (UBC). Many of the writers she’s worked with have gone on to win publishing contracts and honours for their work. Michelle lives and writes in Vancouver, Canada.

David Griffin Brown is an award-winning short fiction writer and co-author of Immersion and Emotion: The Two Pillars of Storytelling and Story Skeleton: The Classics. He holds a BA in anthropology from UVic and an MFA in creative writing from UBC, and his writing has been published in literary magazines such as the Malahat Review and Grain. In 2022, he was the recipient of a New Artist grant from the Canada Council for the Arts. David founded Darling Axe Editing in 2018, and as part of his Book Broker interview series, he has compiled querying advice from over 100 literary agents. He lives in Victoria, Canada, on the traditional territory of the Songhees and Esquimalt Nations.