After a year had elapsed without further sight or sound of her, Nemo had eventually forgotten her. More accurately, she had ceased to think of Cassandra as a real, living person, but she remained aware of the damage the witch had done.
And now, after three years, Cassandra had returned, carrying Merlyn's child. How it had been made was a mysterious matter, and Nemo's blood chilled as she thought of the old women's tales she had heard in her childhood, tales of enchantment and witchcraft, sorcery and the seldom mentioned magic, the arcane, terrifying, secret lore that was named for the learned men who practised it, the magi. She had heard the tales about Merlyn, too, since her arrival in Camulod, tales that whispered that he was a magus, a practitioner of the dark arts, and Nemo was not one to dismiss such a possibility out of hand.
Nemo was convinced that Cassandra, or Deirdre as she apparently called herself now, was a witch, returned as a different person to ensnare Merlyn with the lure of her young body. And that she had clearly been able to do so, in utmost secrecy, was fundamental proof to Nemo that she was right in her suspicions. Merlyn had fallen to the witch's lure, and because of Merlyn's weakness, Uther's peace of mind would soon begin to crumble, and with that her own life would crash in ruin once the word of what the witch had wrought was carried home to Tir Manha.
Nemo knew she had but little time remaining in which to counteract Cassandra's evil, and so she bent her mind to recalling what she could of the kitchen lore she had heard years before regarding the killing of witches. She remembered some fat old woman from her childhood bending over a bubbling pot of stew that steamed deliriously, sprinkling a handful of chopped herbs into the pot and declaring to all the world that there were only two means of inflicting death upon witches without taking the risk of their returning to drag you, screaming, to the fiery underworld. One was fire, the old woman had said, tugging at a burning log and causing an explosion of fierce heat and whirling sparks and embers. A witch burned was a witch destroyed. The other means involved the use of iron, but Nemo could not recall what the old fool had said about it or how it was supposed to be used. The only other thing she could remember from the old woman's ranting was that the iron used to kill a witch could never again be used by human hand. That made no sense to her, now that she came to think of it again, because the iron weapon of any man's choice would be a sword . . . sometimes a spear, perhaps, or an axe, but in most cases it would be a sword. And what fool would risk attempting to kill a witch, knowing that if he were successful he would lose his most valuable weapon? But the task of grappling with that thought was too taxing for her, and so Nemo stopped thinking about it. Either way, she decided, using fire or iron, she would find a way to defeat the witch's designs. She would watch carefully and wait, and then take any option offered to her.
Two days later, Merlyn Britannicus left Camulod at the head of a large body of troops made up of four cavalry squadrons, each forty troopers strong, plus all the support equipment and personnel required to keep such a force in the field for a month or longer, including commissary wagons, a water wagon and extra horses. There were one hundred and seventy-five fighting men in the group, including officers and exclusive of the commissary staff and herd boys, who brought the overall number up to just over two hundred. The expedition made a fine and imposing spectacle as the troopers rode out through the main gates of Camulod and down the winding roadway to the plain beneath, but they were not riding to war. They were headed for the distant town of Verulamium to attend a debate between Christian bishops that would supposedly decide on great and important matters having to do with the gods and how the workings of men's minds in that regard would be judged in times to come. Nemo had had it explained to her by several people, but it all sounded to her like wasted time and effort, and it made her glad she was no Christian. But thanks to all of that, Merlyn had gone from Camulod, leaving his wife behind.
Witnessing the departure that day. Nemo turned her face to where Cassandra, the Lady Deirdre, watched her husband ride away and waved to him each time he turned back to look at her, and her guts burned with loathing, as though she had eaten something indigestible.
She found it surprisingly easy to remain in Camulod unnoticed for the week that followed Merlyn's departure. Nemo was under no great pressure to return to Tir Manha, and so she had no reason to concern herself over being late in reporting there. Her face and uniform had become sufficiently familiar within Camulod to enable her to remain hidden there in the fortress in plain sight simply by drawing no attention to herself and taking great care to remain out of the path of anyone in authority who might wonder why she was lingering so long after she had delivered her dispatches and fulfilled the tasks allotted to her. She simply left the fortress each night and camped, either on the hillside beyond the walls or in the woods by the edge of the training ground below, and it quickly became apparent that as long as she changed her campsite every night, never remaining in the same place twice, she could remain completely unnoticed. She re-entered the fortress each day through the main gates, but revolving duty guaranteed that the guards were never the same from day to day. Her daily visits to the bathhouse were the only part of her routine during that week that had consistency, and they were noticed only by Nennius, who, if he thought at all about the length of Nemo's stay on this occasion, made no mention of it.
For the entire week during the daylight hours, she charged herself with watching the house of Luceiia Varrus, wailing for the Lady Deirdre to emerge and then following wherever she led. The witch seldom ventured out alone, but she came out at least once a day, either with the Lady Luceiia or with one or other of the women of the Varrus household. Even when she did move abroad alone, however, she kept to the busiest public thoroughfares, and Nemo never had the slightest chance of approaching her.
But then, at the end of the week, something different occurred, and watching it unfold. Nemo realized she was watching something that had been planned, and her heart began to race with excitement. The witch, dressed in a gaudy robe of brilliantly bright yellow, rode out of Camulod alone, mounted on a small, light cart with high, narrow wheels, pulled by a single horse. Nemo watched from a distance as a procession of servitors from the Varrus kitchens loaded the cart at mid-morning with a variety of foodstuffs and provisions—clothing and blankets and bedding—and she estimated that the cart contained enough resources to last two people comfortably for perhaps a week. But no second person emerged to join her, and Nemo finally began to hope that this would be her opportunity. Then, sure enough, as noon approached, Luceiia Varrus herself emerged from the house and embraced the other woman, then stood watching and waving as Cassandra rode away alone, handling the reins herself and making a leisurely progress through and beyond the main gates, where she proceeded down the hill.
Nemo followed on foot as far as the gates and watched the cart as it turned onto the eastward road towards the great Roman high road that ran north and south the length of Britain. Then she went directly to the stables and saddled her own mount. After that, it took only a few moments to collect her kit from where she had left it in care of the stableman, and she was soon on her own way, occasioning neither notice nor comment as she walked her horse out of the gates and down the hill. Only when she had reached the bottom of the hill did she kick her big bay gelding into a canter and then to a full gallop, allowing the animal to stretch its muscles while it devoured the distance separating its rider from her quarry in the light cart ahead of them.