Of course, the author of the ordinary tale of this type has the advantage over the real detective, since the author first creates the mystery before solving it. His ingenuity, therefore, will lie revealed in the construction of the crime which he pretends to be unearthing and explaining. Evidently, though, his process of mind can be no different from that of the actual analyzer, who must unravel what to him is a real mystery. He, too, if he is to succeed, must re-image the whole train of events, not as points or dots, but as vivid scenes. Thus only will both workers come at small incidents that are original and ingenious and essentially pertinent. It happened that Poe, in the story of Marie Rogêt, was acting the part of a real detective, since he was reasoning upon an actual mystery, the details of which had baffled the police. In his imaginary case he reinstalled the crime as he felt it must have taken place, and, strange to say—or rather not strange to say, for Poe had the qualities of more than a paper detective—the facts, by a woman's confessions later, were found to be exactly as Poe had imagined them, even in minor details.
Other stories of plot
But stories that emphasize plot do not wholly lie in the detective's realm. There is the pure reasoner's great domain of fancy. "The Lady or the Tiger" illustrates the class completely, even by the whimsical ending. The man that could make up that situation could have solved it, or have carried it on interminably, as he laughingly shows you in the "Discourager of Hesitancy." His "Transferred Ghost" is another quirk, of "reasonable" fantasy. Poe's "Gold Bug" is almost pure plot and has the interesting device of the cryptogram in addition. Pushkin's "Snow Storm" is built upon a queer coincidence.
The story that emphasizes plot is primarily a narrative of a series of happenings, and only incidentally the record of character or place. The author has no interest in what kind of men perform the deeds, except that they shall be the general large types: the soldier and his friend, the lover and his rival, the magistrate and the citizen, the sovereign and his subject, the doctor and his patient, and so on. Interest centers in the question, What will they do next? not, What are they and what will they become?
Romance
In longer prose the story with a plot is the romance, the modern romance. In it, too, the author is concerned mainly with the course of events. Take "Ivanhoe" or "The Prisoner of Zenda," for instance, and what have you?—actors about whom there is no question of character growth. What they were at the beginning, that they are at the end—except, perhaps, Rebecca. In romance the happenings are largely adventure. As they become preposterous the narrative borders on the mere wonder type.
A few suggestions
To write a detective tale or other story of pure plot, you must first get your plot—as the old fisherman would say about the eel when you wish to skin it. If you can grasp one and hold it, you are an expert. The difficulty will be that you will probably find your plot a shadow, when you hoped for a good solid piece of reasoning. In the detective tale you must propound your mystery at the beginning of the narrative and then work backwards to the first step. In the other story, you must start out with the simplest and seemingly most insignificant incident and work steadily up to a fantastic or astounding climax. In the second you naïvely keep adding one to one, as it were, and get a hundred; in the first, you subtract one after one from your hundred until you get a unit.