Ranson's Folly is about the audacious, dare-devil exploits of a junior officer in the U.S. Army, whose position and influence secure a lieutenancy in a Western post. The monotony of the life and its regularity finally drive him into the folly of donning the disguise of a band of notorious highwaymen, and holding up the public coach. The results of this escapade are almost tragic for the reckless young excitement seeker.
The junior officers of Fort Crockett had organized a mess at the post–trader's. "And a mess it certainly is," said Lieutenant Ranson. The dining–table stood between hogsheads of molasses and a blazing log–fire, the counter of the store was their buffet, a pool–table with a cloth, blotted like a map of the Great Lakes, their sideboard, and Indian Pete acted as butler. But none of these things counted against the great fact that each evening Mary Cahill, the daughter of the post–trader, presided over the evening meal, and turned it into a banquet. From her high chair behind the counter, with the cash–register on her one side and the weighing–scales on the other, she gave her little Senate laws, and smiled upon each and all with the kind impartiality of a comrade. At least, at one time she had been impartial. But of late she smiled upon all save Lieutenant Ranson. When he talked, she now looked at the blazing log–fire, and her cheeks glowed and her eyes seemed to reflect the lifting flame. For five years, ever since her father brought her from the convent at St. Louis, Mary Cahill had watched officers come and officers go. Her knowledge concerning them, and their public and private affairs, was vast and miscellaneous. She was acquainted with the traditions of every regiment, with its war record, with its peace–time politics, its nicknames, its scandals, even with the earnings of each company–canteen. At Fort Crockett, which lay under her immediate observation, she knew more of what was going forward than did the regimental adjutant, more even than did the colonel's wife. If Trumpeter Tyler flatted on church call, if Mrs. Stickney applied to the quartermaster for three feet of stovepipe, if Lieutenant Curtis were granted two days' leave for quail–shooting, Mary Cahill knew it; and if Mrs. "Captain" Stairs obtained the post–ambulance for a drive to Kiowa City, when Mrs. "Captain" Ross wanted it for a picnic, she knew what words passed between those ladies, and which of the two wept. She knew all of these things, for each evening they were retailed to her by her "boarders." Her boarders were very loyal to Mary Cahill. Her position was a difficult one, and had it not been that the boy–officers were so understanding, it would have been much more difficult. For the life of a regimental post is as circumscribed as the life on a ship–of–war, and it would no more be possible for the ship's barber to rub shoulders with the admiral's epaulets than that a post–trader's child should visit the ladies on the "line," or that the wives of the enlisted men should dine with the young girl from whom they "took in" washing.