After last week’s post about motive, means, and opportunity, here is something about the crafting of your main plot in a mystery story. This one does also apply to other mysteries, not just to the whodunit. Whenever your story revolves around a question, you can use these pointers to craft your main plot.
Edgar Allan Poe (whose Auguste Dupin predates Sherlock Holmes quite a bit) once wrote in an essay about mystery stories that the best way to write one was from the end to the beginning, meaning by starting with the big reveal of the answer and going back from there. That is a pretty solid suggestion, since the whole story is centred on that plot and on finding the answer. Without knowing what the answer is, there’s no way to lead the way to it.
The very first thing to figure out when you want to write a mystery is, therefore, the solution to it. The answer to the question you’re posing at the beginning is what you’ll use for the story’s culmination. This is the starting point for your main plot, which is all about finding the answer.
Let’s focus on a whodunit again for the moment, although the principle works for every mystery story, no matter what the mystery is. In a whodunit, the answer to the mystery is who did the crime. Minor answers are the motive, means, and opportunity I wrote about in last week’s blog post, but the answer everyone wants is the one to the question ‘who did it?’.
This is the point to start with the plot - the murder. How was it committed? Who is the culprit and who is the victim? What was the reason for it? Once you know all about the murder, can retell it the same way your investigator might if you go for the ‘You may wonder why I have asked you all here’ reveal, this part is done. You now know your answer and you can figure out how to present it best.
Let’s go on from here and line up all possible suspects, because you definitely need more than one for it to be a mystery. Who else has motive, means, and opportunity for the murder? Who else hates the victim or stands to gain from their death in any way? Who else can handle the murder weapon and would have access to it? Who else was in the vicinity when the murder happened? Create two tiers of suspects - some with two of the three boxes ticked and some with only one box ticked. Like this, you have a greater range of suspects and your investigator will have to work harder in the middle of the story. Suspects with only one of the three boxes ticked will be out as soon as it becomes clear that they hardly had a way to do the murder. Those with two boxes ticked are more interesting, because they’re the more likely ones. Your murderer will hide in that tier, do the best they can do to hide that tick in the third box which will make them the prime suspect.
Still, the story will be too simple if there’s only those suspects to tick off as the investigator finds them short of one or two of the three aspects. The next step is to create false leads, to make smaller plots which wrap around the big one. In most investigations, there are other things coming to the surface as well - secrets which have nothing to do with the murder, but are still damaging for the ones holding them. The investigator will encounter lies about the three aspects which have nothing to do with the main case, but merely with other things being hidden out of shame or fear. These complications can only be applied after you’ve figured out the suspects, because they’re related to the suspects.
Finally, the beginning. Figure out how to best present the murder, how to place some initial clues for the investigator to start with. Perhaps you wish to introduce the cast first, give the setting a good look, so the audience can focus more on the murder later. Perhaps you want to go right in with the murder. It’s up to you, up to how you want to write it. The murder or the discovery of the murder make for instant action, which is always a good start for a story because you have an instant hook. On the other hand, many mystery readers, especially when you veer into cosy mystery territory or want to copy classic writers like Agatha Christie, like getting eased into the story, like to get a look at the victim while they’re still alive, so they have a better understanding about why someone would want to kill them.
Once you have decided, your main plot is complete from beginning to end. You may now tag on a little epilogue at the end, perhaps to tie up some additional plots, such as a romantic subplot or a personal development of your investigator. Your main plot is done - you are now ready to write the mystery unless you want to work on the secondary plots a little more.
This works for other kinds of mystery stories, too. Figure out the answer to your question first, add problems in finding it, flesh out secondary plots, and figure out how to begin the story by posing the question well. If you do so, you will always know which hints there are to drop, which makes it much easier to see when in the story to drop them. You can take the investigator and the audience to the red herrings on the way without losing sight of the actual path to the answer. Finally, you can give them a satisfying climax of the story where the answer is told and the answer told will fit with the clues they have seen along the way.
Make sure you’re giving all vital clues to the audience because they expect that. They want to guess along with the main character, create their own theories and change them as new information becomes available. You don’t have to give them the main character’s theories to the answer, that can wait until the end, but they must have the means to form their own opinion.
Mr. Poe clearly was right and it is much better and easier to plot a mystery from the conclusion to the beginning. Whether you wish to write it backwards as well is your decision, but at any rate you will have a solid main plot and the ability to go through the middle without too much trouble about knowing which clues you need to present throughout it.