She shook him off brusquely and climbed the stairs. He came up so close behind that his boots clipped her heels but, this once, she did not berate him for his carelessness. She sensed that at long last they had come to the place where she would learn what she wanted to know.

The stairs brought them up out of the earth into the center of a small stone circle, seven stones placed equidistant from each other on a grassy sward. Beyond, like hulking beasts against the heavens, three mountains loomed. They had not returned to the first stone circle, that was obvious, but Antonia guessed they still walked among the Alfar Mountains.

Her second thought, unbidden and unwelcome, was that it was surely no longer late autumn. The air was clement, the night mellow and almost warm. But the moon remained full, much farther gone in the sky than it had been when they entered the first stone circle. They had walked beneath the earth, guided by the moon’s distant light, for many hours—and it was nearing dawn.

The stone circle stood on a low hill. Beyond, down the slope and half hidden by trees, stood several buildings. The sinking moon still gave enough light that she could make out the rest of the little valley: a copse of lush trees, a few neat strips of cultivated field, a vineyard, squat boxes for bees, a chicken shed, and the leaning wall of a stable set into the steep side of a mountain. A single lantern burned by the gate that led into the enclosure. A stream whispered, murmuring, in the distance. High cliff walls enclosed them, shutting out half the night sky in which stars dazzled, uncloaked by any sign of cloud.

A hand brushed her cheek and she started. “Heribert.”

He stood three steps behind her, too far away to have touched her. He seemed to have been struck dumb.

“Biscop Antonia.” The speaker stepped out from behind one of the stones and made the gesture that in the sign language of the convent signified Welcome. She gave no obeisance. “I am glad you chose to follow my messenger.”

“Who are you?” demanded Antonia, annoyed by her lack of deference. “Are you the one who has led us this far?” She had many more questions, but she knew better than to ask them all at once.

“I am the one who has brought you here, for I have seen your promise.”

Promise! Antonia snorted, but held her tongue.

“You may call me Caput Draconis.”

“The head of the dragon? A strange name, or title, to give oneself.”

“A strange road has brought us all here, and we must tread stranger and more dangerous paths yet if we are to succeed. You are not trained as a mathematicus?” The question was, in fact, a statement, waiting on Antonia’s acknowledgment.

“I know that the constellation known as the Dragon is the sixth House in the great circle of the zodiac, itself called the world dragon that binds the heavens.” Antonia did not like to be toyed with in this manner. She did not like to be reminded that others might know things she did not.

“So it is. And it wields its own power. But the stars do not in their movements gather as much power as do the seven erratica, which we know as the planets: Moon, Erekes, Somorhas, Sun, Jedu, Mok, and Aturna. I speak of the ascending and descending nodes of the moon, where that vessel crosses the plane of the ecliptic. The ecliptic is the path on which the planets move, which we also call the world dragon that binds the heavens. South to north the moon ascends across the ecliptic, and that is the caput draconis, the head of the dragon. North to south she descends, and that is the cauda draconis, the tail. Every twenty-seven days, in the sphere above us, the moon moves from caput to cauda and back again. In every movement we observe in the heavens, there is power to be taken and used.”

“And these are the secrets hoarded by the mathematici? By such as you?”

The woman lifted her hands, palms up and open, empty, to reveal that she needed no weapon cast of brute metal or grown out of earth in order to triumph over her adversaries.

“The teachings of the mathematici are forbidden by the church,” Antonia added.

“And you were being sent to Darre to stand trial before the skopos on the charge of maleficent sorceries whose use is forbidden by the church. I know of you, Antonia. I know your skills. I need them.”

“I tire of this portentousness,” said Antonia bluntly. “Did you compel the daimone? Can you teach me such power?”

“Indeed I can, and more besides. Your great talent is for coercion. I need that talent, for I only possess it in small measure.”

“You have drawn down and trapped a daimone! Is that, to you, possessing only a ‘small measure’ of talent?”

“For compulsion, yes. With the others I can draw down such creatures, but our ability to coerce them is sorely limited. The one you met we could only command to a single task—to find you and guide you to the circle by whose path you then came here. But I cannot, as you evidently can, command spirits and beasts to kill—unless it is already their own desire to do so.”