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All mystery plots revealed!

Attention, readers: here’s how your whodunit ends

Ryan Huddle/Boston Globe

Readers of mystery novels, and fans of TV shows like “The Killing” and “Twin Peaks,” often find that although mysterious questions are exciting, the answers to them tend to be not exciting at all. As an author of mysteries, I know the reason why: The biggest secret in crime fiction is that there are very few ways to end a mystery novel, and you’ve already seen every one.

For the reader’s edification, here’s the complete list, with examples. Get ready to have an entire genre irrevocably spoiled.

1. The Obvious Killer

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“I know it was you, Ignatius Didit. I knew it when you shook my hand, and I saw something dark crusted under your fingernails. I knew it when I heard peculiar noises coming from your basement and decided not to investigate them for some contrived reason. I knew it when your alibi fell apart. I knew it by process of elimination, because everybody else who might have done it is dead. But, really, I knew it the first time I met you; when I visited you at your place of business, I saw that the sign above the door said: ‘I. Didit, Purveyor of Fine Hatchets, Cleavers, and Shovels.’ Your guilt couldn’t be more obvious. The only reason I thought it might not be you for a while is because it seemed too manifestly self-evident. But it’s apparently you. So, I’ve got to say, I’m pretty disappointed.”

2. The Tertiary Perpetrator

A. The Innocuous Bit Player

“Who is that? Oh, it’s you. Yes, I recognized you. It just took me a second, because I haven’t seen you for, like, 200 pages. And, to be honest, you didn’t really make much of an impression when we met. Honestly, I probably wouldn’t have remembered you, except that somebody very pointedly reminded me about you two chapters ago. What are you doing here now? And why have you got that knife?”

B. A Little Too Friendly

“I swear, sometimes this detective job gets to me. Everyone here seems to have some dark secret, and they’re so fast to lie or conceal things from me. It just shatters my faith in mankind. They’re so hopeless. All of them except you. You’ve really been a friend to me, these past few days. You’ve been so happy to divulge everything you know and to tell me all about the reclusive oddballs who live in this Icelandic fishing hamlet where the sun only rises for three hours a day. You’ve helped me keep track of the byzantine genealogies of the feuding local families, and you’ve offered your extensive local knowledge in service of my attempts to identify inconsistencies in their stories. I wouldn’t be anywhere without you, and I hope we’ll remain close friends when this is all over. Why are you laughing so sinisterly?”

C. He Mostly Kept To Himself

“Pardon me, I was just passing by on my way to accuse somebody else of being the brutal serial murderer who has terrorized this neighborhood for the past few months, and I happened to notice an odd stench coming from your apartment. Is everything OK in there? Do you mind if I have a look around? It seems like—OH GOD! OH GOD! OH GOD!”

D. The Crucial Guy I’ve Never Met

“Who are you? Oh. You’re the victim’s ex-fiance. Isn’t it odd that I’ve been investigating the murder for the entire book, and we are just meeting now, for the first time, on page 320? What? You say you eloped with her, and you were secretly married? I guess that explains the receipt for a plane ticket to Las Vegas that I found in her desk, which was an obvious clue that everyone has completely ignored for some reason. But if you’re her husband, and the whole family is dead, then that means...you’re the sole heir to the largest combination yarn store and kitten shelter in all of New Hampshire! You conniving rapscallion!”

3. The Master of Deduction Goes to Work

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“Watson, you’ll notice from these footprints that the perpetrator wears one shoe in a size 9½ and another in a size 11.”

“That seems most convenient, Holmes.”

“Yes, I find things usually are. Now, if you examine the footprint more closely, what else do you see?”

“It looks to be the tread of a work boot.”

“You can see that the boot print contains some red dirt. That’s brick dust. This is very fortuitous, because each clay-bed has dust of a unique color, so I can always tell where someone has come from, as long as they’ve wandered through a brickyard.”

“That also seems awfully convenient.”

“It’s like I always say, Watson: When you eliminate all the inconvenient possibilities, what remains, however implausible, might as well be the truth.”

“Quite right.”

“Now, over here, we have a bit of pipe ash. The leaf from every tobacco store in London is unique for some reason, and therefore identifiable by its ash. I can triangulate the area between the pipe store where this tobacco came from and the brickyard where the dust came from, and then we have only a three-block radius in which to look for the man with the mismatched feet!”

“Extraordinary!”

“And wait! What’s this? Why, it’s the pollen of the African violet, which I can identify on sight even though it’s practically microscopic and looks pretty much the same as any other pollen. There is only one window box in that neighborhood that contains African violets. We have narrowed our search to but a single building, and now I know the name of the man we’re looking for!”

“How is that possible?”

“I don’t mean to be mysterious, my dear stupid Watson. I shall tell you everything, right after I inject myself with a dizzying panoply of recreational drugs, the consumption of which I am certain will never appear ridiculous to future readers of our adventures.”

4. The Big Twist

“Look! It is I! You thought I was dead, but I am not dead. I am still alive, and I tricked you. Also, I am not really a woman; I’m actually a man. I’m the brother of the boy who was hit by the train 20 years ago. I never disappeared. I’ve been here all along, in disguise. Also, are you ready to have your mind blown? You and I are actually the same person. That’s right. We’ve been the same person all along. If you think about it, it totally makes sense. Also, this isn’t really New York City. It’s actually purgatory. But it’s not really purgatory; it’s more like a computer simulation of purgatory. And the computer is a ghost, but it doesn’t know it’s dead.”

Daniel Friedman is the author of “Don’t Ever Get Old,” a mystery novel recently published by Minotaur Books. This essay originally appeared in the online magazine The Millions.

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