Welcome to the Mystery Shark Method!

It’s a mini masterclass for writing a page-turning mystery series.


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True story

Even when I worked for the CIA, diving into real-life mysteries, I’ve been a mystery reader. When I began writing the Detective Emilia Cruz mystery series, drawing on my counterdrug experience, I figured it would be a breeze.


Inventing a compelling main character was just the start. Plots had to be believable enough to keep the reader engaged. Beyond that, each book had to create anticipation for the next.


What the reader wants

Readers love a mystery that pulls them from book to book. Characters to root for or despise. An atmosphere and setting that provides mental pictures of time and place.

As a reader, I want to walk with those characters, turn up clues with them, and wonder if they have what it takes to survive and solve the crime.

The secret

You may have an idea for a mystery series but are daunted by the prospect of actually writing. You wonder if there’s a secret.

What is the secret of the most successful mystery series authors? How do they continually produce top quality books? How do they hook us with compelling settings and characters?

They don’t have a secret.

They have a strategy.

You need a strategy

The Mystery Shark Method is the strategy I used to create the Detective Emilia Cruz series, although I didn’t think of it as such when I started. Eight books later, I’m sharing the steps  to:

  • Build a setting that firmly anchors the series,
  • Create a compelling main character,
  • Craft a lure that builds anticipation for each book in the series, and
  • Keep readers engaged with consistent pacing and plotting.

If you ever wanted to write a mystery series, but have been unsure how to start, this is for you. It’s a 5-part formula that helps you create a blueprint for a mystery series you can be proud to call your own.

The Mystery Shark Method

S = Setting

H = Hero/Heroine

A = Arc

R = Run time

K = Killjoy


Each of the lessons below explains 1 element, with prompts to help you develop your own series. By the last lesson, you will have a blueprint for your mystery series.

This blueprint will be uniquely yours, based on your ideas and experience.


Mystery Shark Method masterclass

The setting of a mystery series is the foundation upon which all the other elements rest upon. You want the setting to be visual. Let readers “see” where the mystery series is located. In this way you will ground the series and make it believable.

Time and Place

Setting means both time and place.

A setting could be:

  • Today’s Oslo, Norway
  • London in 1865
  • Bangkok in 1960
  • A tech-filled future on Mars
  • A small town bakery in contemporary Kansas

The setting creates expectations for the reader. You need to fulfill those expectations by being faithful to the time and place. For example, in Bangkok, Thailand in 1960, the characters won’t use cell phones or know the outcome of the Vietnam War.

The challenge for an author is to capture the mood of a mystery setting with just three or four evocative sentences, especially in the beginning, to avoid pages of description.

When the setting is described, the trick is to not only portray physical environment but capture a sense of emotion. What reaction do people have to this environment? Does it make them happy, worried, tense?

Moreover, setting should be conveyed using all the senses. Sound and smell, as well as visual descriptions are powerful tools to bring the reader into the story.

Sprinkle short descriptions throughout each book in a mystery series. Never try to “front-load” hefty descriptions in the beginning of a book and then leave it to the reader’s imagination for the next 200 pages. You’ll bore, then irritate your readers.

Define Characters

A mystery series can often leverage the setting to show the characters doing something that is only done in that place, such as the legendary guga bird hunt in Peter May’s THE BLACKHOUSE, set in the Hebrides islands off the coast of Scotland.

In Harriet Steel’s Inspector Shanti de Silva mysteries set in 1930’s Ceylon (today’s Sri Lanka) her main character has to navigate the cultural differences between himself and his British colonial bosses that are apparent in dress, food preferences, treatment of servants, etc.

Use local devices to help you build story elements:

  • Holidays and special events
  • Cultural norms
  • Food
  • Physical environment including landscapes, architecture, ocean, landmarks
  • Type of people and professions commonly found there

Think about how the characters relate to the setting. Are the characters from that place, born and bred? Or from somewhere else—the outsiders looking in?

Or have they been gone from the place for a long time and can now look at it with fresh eyes, such as May’s character Fin Macleod who was raised in the Hebrides, left for the mainland, and comes back 18 years later to investigate a murder.

Setting as Character

You can also make the setting a character in its own right. The best example of this is Harry Potter’s Hogwarts. It changes shape, hides secrets, and is a prize to be fought over. Lots of opportunities for action, discovery, and surprises. The right setting gives you an additional dimension with which to create tension and atmosphere.


Readers won’t forget if you get it wrong unless you tell them up front this is fantasy or a parallel universe. They’ll remember if your characters drive on the wrong side of the road or mess up the dates of the Crimean War. If your mystery series is in a bakery, they’ll catch if a cake only bakes for 5 minutes.

Use maps, guidebooks, cookbooks, websites, and reference guides to research and get it right. YouTube is a great resource, too. There is video on whatever it is you want to see to make sure your description is right. When I was researching the first Emilia Cruz novel, CLIFF DIVER, I wanted the big climax scene to take place under Acapulco’s famous Maxitunel. While I’d driven through the tunnel myself, I didn’t recall details. Someone had posted a video of a drive through the tunnel, letting me see the specific placement of lights, the curve of the road, etc.

Fixed vs Wandering

Having a fixed setting, like Robert B. Parker did with the Spenser series, lets an author build consistency and familiarity. Spenser is a private investigator in Boston. The city’s iconic landmarks are often featured as is Spenser goes to Faneuil Hall, Harvard Yard, the famous Locke-Ober restaurant, and the fictional Harbor Health Club. Boston helps the series be consistent and familiar, yet never stale. We know what we are going to get with a Spenser novel and Boston is part of that successful formula.

The same goes for Janet Evanovich’s Stephanie Plum series set in Trenton. There’s always trouble on Stark Street and we want to know how Stephanie gets out alive yet again.

Consistency helps meet the reader expectations we talked about earlier. As an added plus, you don’t have to keep researching new places. Readers who live in that location or have an interest in it (clubs, regional magazines) are already primed to want your mystery series.

But the setting shouldn’t feel like a straightjacket. If you want to set the books in your mystery series in different places, create a home base. Let your readers know where the series comes from. It doesn’t mean all the books in the series take place there. But they come and go from there. Spenser travels to other locations, but Boston is always home. He sees the other places through the lens of his life in Boston.

Martin Cruz Smith also did this with his Moscow-based Russian detective Arkady Renko. One of the best Renko books, POLAR STAR, took place on an Arctic fishing trawler.

Writing Exercise: Setting

When it comes to time and place, the possibilities are endless. The choice for where to set your mystery series is likely to come down to how much you know and how much you are willing to research.

Think of 2-3 possible settings. Answer the following questions for each:

  1. What resources will help me be accurate? List websites, Google Earth, history or science websites, etc.
  2. Does the setting offer unique events, culture, or characteristics that can be used to build a plot or cause tension? List them here.
  3. Why am I interested in this location? How interested am I in learning more?
  4. If someone asked why I chose this location, what would I say?
  5. Is there a local audience that could help promote my series? List libraries, cooking classes, specialty restaurants and stores, reading clubs, professional societies, etc. interested in book signings interviews, and author readings.
  6. After making your lists, which location gives you the most to work with?

With your setting nailed down from the previous lesson, your next job is to design, develop, and deliver a main character. This character is your hero or heroine.

This requires you to answer 2 basic questions:

  • Who will be the main character in your mystery series?
  • What is wrong with them?

In most mystery series, this main character appears in all the books, takes the lead in solving the mystery, and may or may not be part of the mystery itself. Some of my favorites are:

  • Robert B. Parker’s iconic Boston private detective, Spenser
  • Janet Evanovich’s bounty hunter Stephanie Plum
  • Alexander McCall Smith’s Isabel Dalhousie, a philosopher
  • Swedish cop Kurt Wallander from the series by Henning Mankell
  • Dorothy Gilman’s part-time CIA senior citizen Mrs. Pollifax
  • Troubled Norwegian cop Harry Hole by Jo Nesbo.

Does a mystery series always have to have the same main character? No, but it is a great way to build consistency and fan interest. Irish novelist Tana French has been very successful in making a fictional police unit, the Dublin Murder Squad, the main character. Several of her books is narrated by a different member of the squad.

6 Elements of a Believable Main Character

I’ve identified 6 elements to help create 3-D main characters. For each element, sketch out how it applies to your character.

Occupation: While many of the main characters in a mystery series are cops or private investigators, there is really no limit to the occupations you can dream up and how you can use a job to create tension:

What do you know or want to research?

What sort of people would someone in that occupation normally interact with?

Is there equipment, skills, or places that someone in this occupation has to know? Can any of it be subverted for a mystery plot?

Visuals: How old? Ethnicity? Gender? These basic characteristics are essential to give your reader a visual of the character. They also help in terms of marrying the character with the setting.

Are they part of the local scene or an outsider?

Is there tension with respect to how they align with the setting or not?

How can you make the character’s world view accurately reflect their age and experiences?

Education: Don’t just think in terms of formal education.

How smart is this character? How analytical?

Are they street-smart or book-smart? Or both?

Personal likes/dislikes: This is where you can decide the character’s fashion statement, food and drink preferences, etc. In my Detective Emilia Cruz series, Emilia is a cop in Acapulco whose standard work uniform is skinny jeans, tee shirts, and a lightweight jacket to cover her shoulder holster. She’s fond of mojitos and in every book can be found either eating or cooking recipes common to the Mexican state of Guerrero, where Acapulco is located.

How does the character dress? What do they like to eat? Are they religious? These details help you create a view of the character and clues about how they will react and interact.

Family: Everybody comes from somewhere and your character is no exception. Even if they are an orphan (which could be a key part of their psyche) tell us what sort of family circumstances helped shape them into the person the reader meets today.

What type of family is the character from? What issues, if any, does the character have with their parents and/or siblings? Is the character a parent? Are their children grown, young, dead? Are there conflicts?

Back story: Many things have gone on in the hero or heroine’s life before the reader meets them. This backstory can be used to create situations that promote suspense. Emilia Cruz is an Acapulco native forced to grow up too fast, and the backstory begins a process of describing why she is as tough as she is and the circumstances which pushed her up the police career ladder.

The Fatal Flaw

These six elements of character building are your baseline. Not you will add the finishing touch, the element that makes the real.

Your hero or heroine must have a Fatal Flaw. The Fatal Flaw means your character will be vulnerable. Able to make mistakes.

This vulnerability adds a layer of suspense running through all the books of your mystery series without having to think up more plot twists. The Fatal Flaw will create them for you!

It will drive more authenticity, which we know readers love.

One of the best examples of a hero with a Fatal Flaw is the Harry Hole series by Norwegian author Jo Nesbo. Harry is a brilliant Oslo cop with addiction and alcoholism issues. Sometimes Harry’s drug use and alcoholism are in check, other times they send him into a death spiral. Every time, the reader is pulled into his self-destructive yet brilliant narrative. Will the good times last? Or will this be the disaster that ends Harry’s career?

Emilia Cruz’s Fatal Flaw is that she’s an accomplished and habitual liar. The talent serves her well, except when it comes to her interpersonal relationships. Unable to commit, and unable to be truthful, her emotional life is often in a tailspin.

Writing Exercise for Hero/Heroine

  1. Write your character’s backstory, including family relationships, childhood issues/pivotal events, romantic aspirations, education, how they came to be in the situation at the point the reader “meets” them?
  2. What is your character’s Fatal Flaw? List 3 ways in which it can impact the way they approach others and the main challenges of the plot.

By definition, if you are writing a mystery series, you are writing more than one book. Multiple books give you a built-in opportunity to add another layer of suspense with a series arc.

Big plot, little plot

The arc in a series is a big plot or question that remains unresolved until the end of the series or the end of a “series within a series.” The arc can in the background, like theme music, be a continuing secondary plot, or remain an outstanding question. At the same time, each book in the series has its own plot that is somehow impacted by the arc.

Along with quality writing, interesting settings, and relatable characters, the arc is yet another element that pulls readers from one book in a series to the next. Getting to the arc resolved is like a prize waiting for them at the end.

From the author’s point of view, writing the arc is like leaving breadcrumbs.

Think of elements you can use from the baseline created for your series using setting and characters. Can the arc be drawn from a character’s personality or backstory, their occupation, the setting, a conflict between characters, or an enduring external challenge?


To illustrate what I mean, let’s look at some examples:

Harry Potter: How will the link between Harry and Voldemort be resolved? Will Harry ever confront and defeat Voldemort? This series arc is based on conflict between characters.

Emilia Cruz: Will Emilia ever find teen Lila Jimenez Lata, one of the women missing amid Mexico’s drug war? This series arc is based on the setting.

Harry Hole: Will Harry ever sober up or will addiction prove his final undoing? This series arc is based on the character’s Fatal Flaw.

Writing Exercise for Arc:

Determine your arc by casting it as a question.

  1. When/How will X be resolved/found/ended?
  2. What does Hero/Heroine want? What do they need to be able to resolve the arc? Does their Fatal Flaw help/hinder?
  3. What other characters are needed to resolve the arc?
  4. What happens if the arc is never resolved? For example, will the character always have their Fatal Flaw?
  5. Name one or two relationships the character has in every book. Do these relationships help or hinder resolution of the arc?


When you download a movie, there’s usually a notation of how long it is, like “Run time: 109 minutes.” When planning a mystery series, it’s a good idea to decide on your run time, too, by determining two basic things: length and pace.


You want all the books in the series to be about the same length. Popular writer’s blog Reedsy offers these word count suggestions:

Mystery: 75,000 – 100,000

Thriller: 90,000 – 100,000

Cozy mysteries tend to be shorter than suspense thrillers, averaging 60,000 words. Some police procedurals/private detective series authors are also moving in that direction, for an audience used to consuming shorter bites of online content.

Length will determine how many twists and turns you can fit into a single novel. This brings us to pacing, the second element of Run time.


To set reader expectations from the start, plan how fast the action in each book will move.


You may be comfortable writing a book that walks through a clue-studded landscape, like an Agatha Christie novel. Mystery series like Alexander McCall Smith’s No. 1 Ladies Detective Agency and the Thomas and Charlotte Pitt books by Anne Perry move at this pace. It makes for a comfortable, immersive read and ample time to enjoy the stroll.


Alternatively, you may aim for books that set a brisker pace, usually with multiple plot turns. This cadence calls for more physical and/or psychological action sequences and cliffhanger chapter endings. The reader is aggressively pulled from chapter to chapter. Books by Louise Penny, Peter May, and Ann Cleeves are all good exemplars of a running pace.


Many military, psychological, and techno thrillers move at racing speed. This pace is easiest to achieve when your characters are hunted, trapped, on the run, or at war. Action and plot twists happen in tandem. A point of view driven by high emotion like fear, anger, or revenge, also speeds the pace. A great exemplar is STILLHOUSE LAKE by Rachel Caine, with a desperate protagonist who is trapped and hunted yet still fighting.

Writing Exercise for Run time:

  1. List your 5 favorite mystery series. Rank their pacing from 1 to 5, with 5 being the fastest.
  2. Let your reading preferences guide your approach and decide which pace you are most comfortable writing.

Author Ken Follet (EYE OF THE NEEDLE, KEY TO REBECCA, etc.) once said that when writing a thriller, the action has to shift every 4-6 pages. No matter which pace you write, this is a good benchmark to aim for.

A mystery novel generally includes a few plot twists before the mystery is resolved. There’s a red herring or two, obstacles abound, there are multiple suspects, etc. I feel cheated if the Hero/Heroine simply follows clues laid out like a trail of breadcrumbs.


This is my term for all the diversions, twists, suspects-who-are-innocent and other obstacles that preclude a neat and swift resolution of the mystery. Killjoys mess up the trail of breadcrumbs. The more killjoys, the better, in my humble opinion.

Here are a couple of killjoy examples:

  • Misleading or conflicting information,
  • Inadvertent mistake,
  • A deliberate act by one character to conceal or sabotage,
  • Absence of information.

Use your work

This is the work you put in to create a framework for your series will pay off. Your character’s Fatal Flaw and the setting can be used to good effect.

Make a few killjoys unique to your setting’s time and place. For example, when it comes to setting, killjoys in Donna Leon’s Commisario Brunetti series set in Venice are often the result of Italy’s notoriously inept civil administration.

Fatal Flaws make for great killjoys, too. Addiction is the Fatal Flaw of Oslo police detective Harry Hole, brilliantly written by Jo Nesbo, and creates multiple killjoys that impede his investigative work, notably in KNIFE. Alcoholism is a complicating Fatal Flaw for the Kurt Wallander series by Henning Mankell, the John Rebus series by Ian Rankin, and many others.

Beyond the killjoy

How can your characters solve the mystery despite the killjoys? Here are some ideas, drawing from the Detective Emilia Cruz series:

  1. Snitch (also known as stoolie) on the street tells her: Emilia pays somebody for information.
  2. Online research and discoverability: criminal posts a YouTube video, information is about a business with a website or listed in a business registry, etc.
  3. Part of a parallel investigation: another cop finds out something relevant to her case and shares it.
  4. Forensic evidence: DNA testing; fibers or dirt provide context and additional information, tire treads, etc.
  5. Anonymous caller: tip comes in through a hotline or to police station.
  6. Ballistics: gun used has a history known to the police.
  7. Autopsy results: something about manner of death or body provides important information.
  8. Cold case files: the current case is linked to a past unresolved case.
  9. Photography: video or still photos capture information relevant to her case.
  10. Witness: witness tells all.

Writing Exercise for Killjoy:

In this exercise, you are going to reverse engineer some killjoys:

  1. Select a book you consider a role model.
  2. List events or actions that led in the wrong direction or prevented easy resolution of the mystery.
  3. Was there more than one killjoy?
  4. How many steps would it take to resolve the challenge if there were no killjoys?
  5. Would the book be more or less interesting without those killjoys?
Carmen Amato at Spring Hill

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