Why Plotting a Cosy Mystery Is Harder Than It Looks — and the Tool I Built to Help
Cosy mysteries look deceptively simple.
There is usually a pleasant village or small-town setting. The violence is kept off the page or described discreetly. The cast is manageable. The humour is gentle. The amateur sleuth notices what everyone else has missed. By the end, the culprit is exposed, the community settles down again, and normal life resumes.
From the outside, it can all look rather effortless. It is not.
I discovered fairly quickly that writing a cosy mystery is one thing. Plotting one properly is quite another.
The prose may be cosy. The plotting certainly isn’t.
A fair-play mystery has to do several jobs at once. There must be a culprit with a believable motive. The culprit must have had access and opportunity. The method has to work. The apparent explanation has to make sense for long enough to fool the reader, but not so completely that the final solution feels like a trick.
Then there are the clues.
A clue needs to be visible to the reader, but not necessarily understood at the time. Ideally, it should have an innocent interpretation when it first appears and a more important meaning later. It should help solve the mystery without announcing the answer too early.
And that is before we get to red herrings.
A good red herring is not simply a character who behaves suspiciously because the author needs someone to look guilty. That person needs a genuine reason for lying, hiding something, returning to the scene, changing an alibi or removing an object.
They need a secret. But it needs to be the wrong secret. That distinction matters.
If every suspect behaves suspiciously only because the plot requires it, readers notice. They may not be able to explain exactly what is wrong, but the story starts to feel artificial.
Then everything has to be distributed across the book.
You cannot put all the useful clues in Chapter Nine. You cannot introduce a vital object for the first time during the final explanation. You cannot let the murderer escape suspicion simply because nobody bothered to ask the obvious question.
The mystery has to be fair.
That is a lot of machinery hiding underneath what may be a very gentle story about flower shows, village cricket, bowls clubs, amateur dramatics or harbour festivals.
For some time, I dealt with this in the usual way. I made notes. Then I made more notes. I created lists of suspects, motives, clues and chapter events. I tried worksheets. I made tables. Eventually I had enough planning material to make a small government department nervous.
The trouble was that many plotting systems simply replace one blank page with twenty smaller blank boxes.
Victim:
Motive:
Method:
Clue One:
Clue Two:
Red Herring One:
Final Proof:
That may be helpful when you already know the story. It is less helpful when the reason you opened the plotting tool in the first place is that you don’t.
I began to think there had to be a better starting point.
Instead of asking a writer: “What is your mystery?”
What if the system said: “Here is a complete mystery. What would you like to change?”
That turned out to be the important idea. Blank boxes are work. Pre-filled answers are choices.
There is a surprisingly large psychological difference between inventing a murder method from nothing and being shown one and thinking: “No. I don’t like that. I’d rather the murder happened in the potting shed.”
Once you disagree with something, you have started creating.
That was the idea behind the Cosy Mystery Plot Creator.
It began as an Excel workbook because I wanted something practical rather than decorative. I wanted to be able to choose a scenario and see the pieces of the mystery laid out clearly.
The first versions were much simpler than what eventually emerged.
Over time, the system grew to include the things I repeatedly found myself needing as a mystery writer.
A complete scenario. An apparent event. The true incident.
A reason the culprit acts now rather than six months earlier.
A believable form of access. A method of deception or staging.
Three suspects who appear guilty for different reasons.
Get Aginthecloud’s stories in your inbox
Join Medium for free to get updates from this writer.
Five clues that actually contribute to the solution.
A midpoint development. A late twist. A final reconstruction.
And, crucially, some idea of how all of that might fit into chapters.
The current Full Edition contains 250 mystery scenarios. That number is useful, but it is not really the point. The point is what happens when you choose one.
Suppose I decide I want a coastal sabotage mystery. I might select a regatta scenario. Immediately, I am no longer facing a blank page.
I have an event. I know what has been sabotaged. I know who benefits. I know why it matters now. I have suspects, clues, innocent explanations for those clues. I have a staged explanation for the incident. And I have a ten-chapter structure showing roughly where the investigation can go.
I may use half of it. I may change nearly all of it.
But I am reacting to something. That matters enormously.
The Plot Creator now has two main ways of using it. The first is Quick Outline. This is for the days when I want the machinery done quickly.
Choose a scenario. Choose one of five Story Versions. Keep or change the supplied names. Review the red herrings. Review the five clues. Read the ten-chapter outline.
Then start writing.
The second route is Simple Guided Creation. That is for times when I like the basic mystery but want more control. I may want a different culprit role. I may want the strongest red herring to be a family secret rather than a financial problem. I may want to change the setting or to rewrite a clue so it suits my characters.
The important thing is that I am still editing a complete structure rather than constructing one from loose parts.
There are also different Story Versions. The same underlying mystery can be presented as a Classic Investigation, a Suspect-Led Mystery, a Setting-Led Mystery, a Clue-Led Mystery or a Character-Led Mystery.
The culprit remains the same. The core logic remains fair. But the route through the story changes.
That has proved particularly useful because two books can share the same broad type of mystery without feeling as though they have been written from the same template.
One might revolve around the physical layout of a harbour. Another might spend more time among the suspects. A third might depend heavily on the reinterpretation of a small object seen early in the story.
The Plot Creator is not there to write those books. That part still belongs to the author.
It cannot provide your voice or create the precise rhythm of a conversation between two characters you know well. It cannot decide that an elderly neighbour should interrupt an interview because she has brought a Victoria sponge nobody asked for.
And I would not want it to.
For me, the useful distinction is between story engineering and storytelling.
The Plot Creator helps with the engineering.
Who did it? Why? How? What did they fake? What mistake did they make? Which clues expose it?
Why do three innocent people look suspicious? How can the truth emerge fairly over ten chapters?
Once those questions are reasonably secure, I can concentrate on the part I enjoy more.
People. Place. Dialogue. Atmosphere. Humour.
The awkward silence after someone says slightly too much. The character who notices a detail but does not yet understand it. The village argument that appears trivial until it turns out not to be. In other words, the story.
I also wanted the tool to reflect the kind of mysteries I enjoy writing. That means village settings, clubs, societies, heritage locations and increasingly a strong East Devon flavour. Some of the scenarios are inspired by the atmosphere of Sidmouth, Exmouth, Beer and Seaton. That gives me beaches, promenades, cliff paths, harbours, hotels, sailing clubs, nature reserves and heritage transport to work with.
But the same principle applies whether the story happens beside the sea or in a parish hall.
The setting should not simply be somewhere attractive to put the body. It should contribute to the mystery.
Who can get into the building? Who has a key? What does the tide change? What can be seen from the footpath? Which door is normally locked? Who is expected to be backstage? What looks innocent because everyone in that community does it?
Those details are where cosy mystery plotting becomes interesting.
I eventually made a small Free Starter Edition containing five complete scenarios because I realised the easiest way to explain the idea was to let people try it.
It includes a murder, a theft, a fraud, a sabotage mystery and a disappearance.
The point is not to give away five finished novels. It is to demonstrate a different way of beginning one.
Instead of staring at an empty page and asking: “What happens?” you can begin with: “This is what could happen.”
Then the real creative question becomes: “What would I do differently?”
For me, that has turned out to be a much easier question to answer.
Where can you get the Cosy Mystery Plot Creator?
