Introduction: Carlo sees an angel descending from the skies; upon alighting, the angel becomes a nun; Carlo tells the sister of the demon that besets him and she helps him fight it; another day, the nun returns and they do battle with his demon again; at last Carlo can take the battles no more and sends the nun off to find other demons.

Know, then, that in the woods outside our city lived a poor man, Carlo, some fifty years of age, who eked out a bare existence farming the poor soil in a small clearing he had made; and he had been married once, but lost her to an itinerant tinsmith, who, taking away Carlo's bedmate, condemned him to a life of solitary pleasures, such as they were. One day -- it being too early in the spring to plant, and yet pleasant enough to tarry out of doors -- Carlo was sitting on a stool outside his little shack, watching the clouds roll past the small opening in the trees that surrounded him, when a bit of movement captured his eye, and he, looking at it, rubbed them for a moment. An angel! Or so it appeared, for as the vision drew nearer he could see that it had something of the manner of a human, in a robe, but truly there were wings, for it was flying through the sky!

Still lower the vision came, and now Carlo could see more clearly through his rheumy eyes, and the angel had an angel's face, round, like a cherub in the old, thick Bible on his top shelf; when it drew still nearer, though, it appeared this angel wore shoes.

At last the vision drew very near, and the angel seemed to be verily a fallen one, for its hands were flailing and its feet nearly touched the treetops; it cleared them, though, and the angel descended into the clearing, landing but a few feet from Carlo's stool, he having risen to greet the apparition. But greeting it, Carlo was hushed, for the angel told him she was, indeed, not an angel, but rather a nun from the nearby convent; she explaining further that the wings were those of her habit; she having been perhaps the lightest ever to wear the habit, it was found that a stiff wind could render her airborne, but she had not fully mastered the art of flight and sometimes was forced to land whither she could, rather than whither she would.

Carlo heard her words, and understood, but still marveled at the sight; then a twinkle in his eye appeared, and he addressed her thus, saying, "Be you not an angel, still you may be sent by one, for I have a demon that I cannot slay. Perhaps you were sent to be my strength." The angel, who calleth herself Sister Bertrille, expressed puzzlement at the nature of this demon, for though she was but still young she had listened to the words of the old and she did not believe demons still roamed the land. But, lo, he told her, his demon did not roam, but had entered Carlo's own body, and tormented him day and night; whereupon he pointed to his lap, and truly Sister Bertrille could see that something had taken possession of the man, for a large bulge had appeared there and was growing as she watched.

"This is my demon," Carlo told her, "and a wicked demon it is, for it issues forth from me and I must battle it, trying to force it back in, lest it erupt and take with it my very soul; but it resisteth my struggle, and only after much toil can I subdue it. Alas, I grow weak, for I have not the strength of the young, nor the grace of the godly."

"Tell me what is required, and I will battle your demon for you," the nun said; and thus Carlo told her, drawing forth the demon from his pants and laying it in his lap. "Oh," Sister Bertrille said, "surely I can see it is a demon, for it has but one eye, and that an evil one." "Yes," Carlo told her, "but we shall vanquish it and force its bile to issue forth, and I shall have peace." And so, following his instruction, Sister Bertrille grasped the demon in her soft hands, which had never known hard work, and Carlo said that it was good; whereupon he urged her to push the demon into him, and she attempteth to do so by pressing down on the head, but the demon was cunning, and resisteth, and Carlo cried out in pain, and said the demon was too strong, but might be conquered by another method. Whereupon Sister Bertrille began to rub her hands up and down the demon's length; it grew longer, and thicker, and seemed to stiffen, but Carlo said that he felt it was working, and urged her continue. Which she did, rubbing her hands mightily until Carlo began to groan, and she would stop; but he urged her on, through gritted teeth, and she did, and the demon at last leaped in her hands, and issued forth its bile, and sank back.

Thus did Sister Bertrille conquer Carlo's demon, for which he thanked her mightily, but she being a modest nun, declined his thanks, and a stiff wind now coming through the trees, she lifted off and flew away.