At first I didn't see the daemon, only the girl my father had given to it as a sacrifice, my twin. Mechanical columns mounted on corroded gears turned heavy bronze mirrors to reveal the monster. Ahriman was invisible to the naked eye, but his form was reflected clearly by a particular alloy of polished bronze and tin. He was hulking, twice as large as a man, with a double set of ram's horns on the sides of his head like twin bony fans. Thick, wet lips curled to reveal stubby fangs and a purple tongue that stretched as long as a human arm. Scars and scales patched his rhinoceros skin, his lower half naked and nearly human.

My eyes stung. "How could you?"

"I did what was necessary to preserve the kingdom." The High King, my father, touched my shoulder with a gentleness he rarely showed. "I understand what you must be thinking. It's what I thought when your grandfather brought me here."

Grandfather Lao? The man who'd sailed into the sky when I was a girl? My memories of him mostly involved gifts of candies and small animals I wasn't capable of taking care of properly. He told naughty jokes and said mean things about the court officials to make me laugh. The man had never stopped smiling. How could he have smiled like that if he knew about this?

"No one sees this chamber apart from the royal family," my father said. "It's our burden alone."

"Why?" For all its horror, the daemon and its wagging tongue was less terrible than the sight of the young woman who looked like me. Given our different circumstances, if it had not been my own face in the dim light I wouldn't have recognized it. My nose, a bit short and slightly upturned, and those moon grey eyes. It looked as if her hair had never been cut, hanging in rank clumps over her body. For clothing, she had nothing but a shredded blanket, her feet bare against stones that were so cold there was frost visible in their interstices. My twin showed no sign of noticing us, her stare as vacant as a sow's.

"IT IS OUR BARGAIN." Ahriman's voice was physically powerful, it resonated in the hollows of my being. "YOUR FAMILY STRUCK IT LONG AGO."

I recoiled from the daemon, my sister, my father, but there was nowhere for me to go. Three concentric cages composed the prison; the outermost cage we occupied. The middle cage was tiled with the 72 signs of the holy compass, the symbols instilled in me by endless drills and exacting tutors, the whole combining into a magic circle around the inner cage that held the daemon. The sacred magic of my family, the Longues, passed down the generations, was all that kept this beast at bay. My father had locked the gate behind us, so I pressed myself against the bars and could go no further.

"It speaks the truth." My father looked pained. The robes and gems of his office were made dull and grimy in this chamber. "This is the source of the power that preserves Euphoria. Our kingdom depends on this bargain to survive."

"My sister..." There had been whispers when I was very young, how my mother had died giving birth to twins. The servants who had let the existence of my twin slip had been banished from the palace, but I had still played games in my mind wondering what it would have been like to have a sister. They said that my twin had died along with my mother, an unbelievable tragedy, given births in Euphoria were the safest anywhere. Would-be mothers from other kingdoms sometimes made the long and difficult journey up the Atlan mountains to have access to our medical knowledge. I had always wondered how my birth could have gone so wrong for the High Queen, the best prepared and protected woman in the world. In the heart of night I'd wondered what could have been so wrong with me, that I had killed them both. "You told me she was dead."

"She is." My father hardened, changing roles, becoming king. "A choice was made between you according to the prescribed methods. The firstborn daughter of every generation. It is why our family has so few girls. We were blessed that you were twins, to be able to keep my daughter, my heir, even while losing my queen."

"What really happened to mother?"

The king was not a tall man, but he had a way of towering over me. "I would never have hurt her. Do not even think it. Her death was an unpreventable tragedy."

Beyond my father, in the polished brass, the daemon slowly winked at me.

"I'm sorry, father." I lowered my gaze. It was a reflexive response to his ire, overwhelming under the circumstances. I blinked my eyes clear. "I did not mean to accuse. I am beside myself."

"Of course." He deflated. "This is a difficult thing to see. Difficult to understand. You are a woman now, and you will soon be married. That is why it was necessary for you to be prepared. As my only heir, it will fall to you to preserve our kingdom."

"Can we help her?" I didn't want to look again, but it was as if a hand was lifting my face to see. My sister was crawling to the center of the demon's circle, her eyes glassy and vacant. Ahriman was a vague shimmering in the air, but in the mirrors he showed clearly, his long tongue rasping along the exposed skin of her back.

"There is no one there." The king said. "The child that is given to Ahriman is given completely. Her soul is devoured, and the husk is put to rest when we give the daemon the next sacrifice."

"Put to… you're going to kill her?"

"Your sister died soon after she was born," he said. "Do not ask after her again." There was still that pain, but the anger was for having questioned him.

"Let me out," I said. "Please."

His expression was one of restraint. "It's enough for one day that you have seen this, but you will have to return to take the oaths after your betrothal."

My breathing was shallow, and there was a scent like incense burning in the back of my throat. It was the incense burned at funerals. Ahriman was an idea, the legendary daemon that ruled over the spirit realm and whose notice invariably brought misfortune. Of course spirits were real, our nation was founded on the High King's mastery of the spirit realm, but the idea that a living god was bound beneath the palace was beyond all reason.

The king moved past me and removed an ornate ivory key from around his neck. The key to the realm, a symbol of office more powerful than the white jade crown that adorned his head. The key had always been a symbol, not a tool. There was gossip that it opened a secret chamber in the treasury filled with diamonds and jades of all colors. What would the people whisper if they knew what was really at the palace's heart?

"Go," The king said. "We will speak more on this later. This is our solitary onus, and you must not reveal it to anyone. Your grandparents are the only others alive who know."

My grandparents, both in their nineties, and one of them not seen in years. They'd been keeping this from me my entire life.

"Yes, lord father. I will respect your wishes." I slipped by him and out of the cage, the air clearing immediately. My sister hadn't so much as glanced in my direction, but her eyes hounded me nonetheless. Ahriman, Architect of Tragedy; it was said our kingdom was hidden from his influence by the clouds and by the wisdom of the royal line. Rather, we kept him caged in our cellar, satisfied with our own blood.

The chamber of cages was beneath a maze of empty corridors below the palace, remnants of what had once been a gold mine that had long ago been scraped clean of all valuable minerals. No one came to this place, but it was not forbidden. There was no guard or warning sign. I'd explored the abandoned mine with other aristocratic children years ago and we'd found it too boring for a second look. What if we had stumbled on the chamber then? How had no one ever stumbled on it?

I took one of the torches from its sconce outside the heavy stone door to the chamber and noticed a diagram worked into the wall. It was a combination of holy sigils, the mark of shadows. Sorcery kept this place unfound.

Dozens of branches and turns led above to the palace larder. Navigating the nearly identical passages was second nature for me. I wished that it required more effort, to keep my mind off what I'd seen, but memory games had always been a talent. After today, my memory would be a curse.

Ahriman's tongue was rough like a cat's, scouring my sister's skin. There had been nothing in the inner circle but the two of them and a layer of filth like the detritus of the forest floor. Had there been anything in all these years? One word of kindness, one gift of love? While I had grown into a woman of means, a princess and heir to Euphoria's throne, my sister had suffered in darkness. All because of what, a spin of the compass? Had my father done the divination himself, my grandfather, grandmother? If the secret was that closely guarded it had to have been one of them. What of my tutors? The court historian? Did none of those learned men suspect the foulness in the heart of the mountain?

The torch was no longer necessary, so I placed it in another sconce by the entrance to the mine. My body was moving on its own as my brain unravelled. Servants saw my reddened eyes and wondered what could have touched a princess known for her good cheer. Some of them took it as an omen and whispered prayers to the ancestors to look after me. My ancestors had done this to our land.

I found myself in the garden, a tiered terrace overlooking the clouds below the palace. The sky was an immaculate blue running to indigo at the edges, and the peonies were in bloom. Pink and red and yellow, and most prized of all, red with gold trim, the royal strain. Their gentle fragrances filled the cold air, washing over me and washing away the cloying stench of incense on my clothes. I went to sit among the flowers and gaze down the mountain steeps. Often I had daydreamed what it would be like to dive through those clouds with wings outspread, never before had I imagined jumping.

"Joi, are you okay?"

The voice seemed to come from far away. A young aristocrat fostered by my family, Cratos always managed to appear a little awkward in the silk vest and trousers common to the palace. They wore robes and tunics in his homeland, Gracia.

I wiped my eyes. "I'm fine. The beauty of this place overcomes me."

He looked unconvinced, mouth quirked as it did whenever he was puzzling. "As you say," he said, letting it pass. "I've actually been looking for you."

"Oh?" Cratos was a good friend, but I wanted him to disappear.

"Seeing as you will be a promised woman soon, I thought you might like to go for a sail." He crouched beside me, dark hair framing a handsome, honest face. He wasn't a prince, exactly, the Gracians didn't have princes, but the equivalent. He'd been a gangly boy when he arrived, and the fact that we'd been able to grow up together spoke to his father's ability to retain power. The gracian fosters before him had lasted a year or two each for as long as I could remember.

"It may not be a day for sailing," I said.

Cratos made a show of surveying the perfect sky. "Not a day for it? You might be right, it wouldn't be interesting for a sailor like you without a storm or an irritated koi to chase us."

"I'm not feeling well."

"Exactly the reason to come with me."

Euphoria was carved into the slopes of the Atlan mountain range overlooking the Sung steppes. The vast majority of the nation's population lived in Cloud City, the rest scattered in forts and outposts among the cliffs and defiles of the range. The smaller settlements were largely self-supporting, enjoying the bounty of the kingdom without need of constant commerce. Our people were healthy and independent, and the crown, rather than requiring taxes from its conscientious citizens, was the source of all real wealth. This model of government existed nowhere else in the world because it could not exist anywhere else. Now I understood why.

Castor and I strolled along the palace wharf where the fleet was moored along with a few pleasure boats belonging to the court and foreign aristocracy. His father owned a twenty foot skiff with a silver griffon worked onto its prow.

"There she is," he said, waving to one of the attendants. A plank was unfolded so we could walk onto the skiff where it floated in a cottony bank of clouds. "I know she isn't the grandest thing, but I'm fond of her."

"Why can I imagine you saying that about your future wife?" I said, smiling for the first time since the dungeon.

There was a hitch in his step, minor enough it almost passed my notice. "I wouldn't say that," he said, suddenly bashful.

Castor really was a good friend. Whether by accident or design he'd brought me to the one thing I loved unreservedly, the one thing that could help me push my shadowed thoughts away. Sailing isn't quite as good as having one's own wings, I imagine, but it must be the second best thing.

He unmoored us as I tapped the ship's compass to wake its daemon, we'd started to drift as soon as we were free of the wharf. Air is never really still, as empty as it may appear.

"Where are we going?" I asked.

"I thought we'd see the sea." Castor still seemed embarrassed about something, he was having trouble meeting my eyes. I was almost glad for it, another distraction to be worked out.

"East or North?"

Castor manned the rudder and turned us north-east, we were going around Cloud City. The rudder was an affectation meant to make actual seafaring sailors more comfortable. The compass was the proper way to direct a sky ship, and to communicate with its daemon for information about the weather and air currents. The 72 holy symbols of the diagram were etched into iron on all our ships, echoes of their massive stone mirror around Ahriman.

"Look." Castor pointed to spots of color like drops of blood along the slopes. The azaleas were in bloom. The sight of the city and its flowers never failed to steal my breath. Cloud City was an endless ramble of mist graced marble and granite architecture. Arches and braces and turrets, we didn't have castles exactly, didn't need them, but the ancient builders had borrowed from military designs in a way that made them inviting and invigorating. There was so much strength in these mountains, and all of it laid out in perfect order that only appeared like an accident. From my studies, I knew the city plans had been painstakingly measured and applied to create a magic circuit on a titanic scale, yet another chain around the beast below.

I had to look away. I was nearly sick. Castor locked the rudder to check on me as I gripped the rails. Such fine, smooth wood, I couldn't even feel the grain. The air was cool against my cheeks, and I swallowed hard.

"Not airsick, are you?" He said, worried, but trying to joke.

"No, I'm fine." The clouds parted beneath us and I could see the foothills miles below. The sight would have thrilled me on any other day, and now I felt nothing but dread. It wasn't fear of falling, but of the understanding I couldn't keep from seeping into my mind, as pervasive as the incense in that cage.

"I understand if you're worried." He said, "at our age, there's a lot to be worried about. Decisions to be made...you'll be seeing the matchmaker soon."

What? Oh, my upcoming engagement. To think, that had been my only problem a few days before. It was an anxious time for any young woman, not knowing whom they would be paired with. No matter how much you trusted the compass to show the right path, the unknown was always unnerving.

I wished that I only had to worry about the unknown.

"Do you have any idea who will be on your list?" He touched my shoulder as gently as my father had done and I flinched away. He looked hurt, but I didn't have the words to mend it. It isn't you, I thought, it isn't this.

The airships were kept aloft by bound daemons, spirits of the earth and sky locked in suspension. The magic of the royal family kept the entire fleet afloat, kept us literally above the nations that might otherwise overwhelm us.

I'd always accepted that it was my place in the universe to use the diagrams, that when I was older I would use the sorcery of my ancestors to protect our kingdom and preserve its peace. Now I knew what that would cost. I had never questioned why our line alone was gifted, why we alone commanded daemons.

It wasn't a command at all, but a bargain. We'd struck a bargain with the king of daemons and by his authority our ships were made to fly, our rocky slopes bore endless fruit, and our medicines were plentiful and pure. The compass built into the ship, the compass that was the city itself, it was all a part of Ahriman.

"I wanted to tell you," Castor went on, "that I asked to be considered as one of your matches."

"Oh," I said numbly, "thank you."

He returned to the rudder, and took us to the sea.