A Calculus of Angels by J. Gregory Keyes

“Mademoiselle de Mornay de Montchevreuil.” He doffed his hat.
    It had been so long since Adrienne had heard her family name, she nearly didn’t recognize it. A name from another lifetime.
    “You have the advantage of me, sir.”
    “My apologies, Mademoiselle. My name is Hercule d’Argenson. I—” He knelt next to Crecy. “—I regret that we meet under such circumstances. How is she?”
    Adrienne raised her eyebrows. “You know her.”
    He nodded. “She was a member of the Hundred Swiss, once. Posing as a man, of course, but a few of us knew. I was a friend of Nicolas d’Artagnan, Mademoiselle. We all envied him, that he was your guard.”
    “He was ill served by it, as Crecy has been. I do not think she will live.”
    “We will do what we can, I assure you. My doctor is nearby.” D’Argenson smiled faintly. “I know that you may doubt it, but your company has improved.
    We are not cutthroats, like these fellows.” He gestured at one of Le Loup’s men who lay dead not far away.
    “I am relieved to hear that.”
    “I thought you might be.” He regarded her for a moment. “I will tell you of it in A CALCULUS OF ANGELS
    a more comfortable place. Here, we are in danger. Indeed, you are fortunate that we found you. Soon, this may well be a true battlefield.”
    Adrienne shrugged. “I do not even know where I am,” she replied.
    “Presently, it is a part of Lorraine,” he said. “But in a few days, time, I fear it shall be Muscovite soil.”
    They reached the main road from Nancy near nightfall and found it flooded with a stream of men, women, children, beasts, and creaking wagons.
    “Where do they think they are going,” Adrienne wondered, “that will be better than whence they came?”
    “They would rather take their chances in the countryside. Evil tales are told of the Muscovites,” d’Argenson replied. “Some say they are sustained by the blood of their victims, that they have made pacts with the prince of hell.”
    Adrienne absently stroked the mane of the horse d’Argenson had given her to ride.
    “They will find nothing in the countryside,” she told him.
    “How well I know, Demoiselle.”
    They moved upstream through the stream of refugees for a few hours but parted from it before reaching the town, following instead a smaller track which quickly gained in elevation, until the horizon stretched out behind them as a blue smoke. Above, a few blurred stars shone down, and Adrienne remembered a night, long ago, when she had lain with Nicolas d’Artagnan and beheld a sky of jewels, and known that she was in love. She had been twenty-one, then. Now she was twenty-four, and could only just barely recall the feeling, and could visualize the splendor of a clear night not at all. She absently stroked the head of her child, the namesake of that lost love, wondering if he would ever see the stars that clearly.
    The road tunneled through a dark wood, but after a time, the light of many campfires appeared. Sentries questioned them and they entered a city of camp A CALCULUS OF ANGELS
    sites. They passed near some men who were singing a bawdy but not unpleasant song. Her nose twitched at the scent of meat, a rare thing these days.
    They rode between stone gateposts grown over with ivy, across ill-tended gardens to a manse in the style of two centuries before. There, liveried servants hurried out to meet them, and Crecy was borne off by a pair of soldiers to where d’Argenson assured her a doctor waited.
    D’Argenson dismounted and then offered to help her down, but she had already taken her son beneath one arm and thrown a leg over the saddle. She grinned ruefully at his extended hand.
    “I have not been in the company of gentlemen in a long time,” she apologized.
    “That is the loss of gentlemen everywhere.”
    “You are gallant. I know what my appearance must be.” Her hair was a rat’s nest, her stolen dress in tatters.
    “A diamond is always a diamond.”
    Suddenly embarrassed, she