When the night draws its curtains around the city, and my family has gone to bed, I creep from my room. On light feet, I run to the library in my robe, determined to find out what lies in the ceiling above all those books. Who knows if it can help, but I must satisfy my curiosity.

Mama and Papa were subdued at dinner tonight, but still refused to listen to reason. They shut me down when I tried to speak of the wizard. "Not in front of your sister," they said. "You'll scare her."

Haven't they noticed she's already scared? Delia is more observant than any of us give her credit for, which is why I glance behind every few seconds tonight.

When I reach the huge doors of the library, I hear a soft noise, and Ren's form breaks free from the shadows. He wears a mischievous grin. "Come on," he says, reaching out his hand. I take it.

We creep through the aisles, between the stacks of moldering tomes, then upstairs and around corners. Every inch is packed with the knowledge our kingdom has collected over the centuries.

With all this mess of books out here, what could be behind that door?

When we reach the top level, the last step creaks, echoing off the rafters in the otherwise silent room. Ren and I hold our breath for almost a full minute before deciding no one heard us.

At the northernmost edge of the top level we are faced with another problem.

"How are we going to get up there?" Ren says.

I scan the walkway for a moment. "This," I say, heading for the ladder used to reach the highest shelves. "This should give us the boost we need."

We wheel it over together, positioning it beneath the northern compass point. "Ladies first," Ren says.

Getting to the compass point, a gold filigree star-shaped design, is easier than I thought. Figuring out how to get it to release the panel is more difficult. Pulling and pushing have no effect, and it won't even budge enough to turn. "We're missing something," I say.

"Missing what?"

"I don't know, that's the problem." I tap my fingers on the top of the ladder. "It needs to move for us to get behind there but it's like it's locked."

"Let me try," Ren says. I come down and he hurries up the ladder in my place. But it's no good. He twists and cajoles with the same result: nothing.

He hops back onto the floor. "You're right—we're missing something."

"I've been thinking," I say slowly. "What could unlock a compass point?"

"Compasses are used for navigation. So perhaps something to do with the ocean?" Ren considers this idea, then his face lights up. "Perhaps the key is hidden in a nautical book of some kind, or a pirate history?"

I straighten up. "Yes! Or maybe even a map?"

Ren takes in the whole of the library—we can see almost every book from our vantage—and groans. "Do you think we'll find the key before dawn?"

I bite my lip. "I hope so."

We get to work, but none of the histories or archived captains' logs shed light on the trouble here in the library. We end up seated on the floor with piles of scrolls and tomes surrounding us. When I sneeze for the seventh time from all the dust, Ren leaps up from his chair. "It can't be a book. Let's try the maps and nautical instruments on the third tier. Or maybe one of the weapons exhibits."

"All right, but how could those things help?"

"I have an idea." Ren heads for the section that holds the maps. I follow, intrigued. "The ceiling is divided as a compass, right?"

"Yes," I say.

"Another navigational tool was a sextant. And that we could find with the antiques . . . if we're lucky," Ren says as we reach the maps. Two whole walls are piled high with them. He handles the maps with great care as he looks through them

"You've looked at these before, haven't you?" I say.

He glances up, surprised. "I may have snuck in here once or twice before."

Of course he has. Ren and I grew up together, and for a time we even shared a tutor. Papa holds Ren's father in the utmost respect and wanted to be sure his son had a good education. Ren always livened up on days the tutor taught us history, and the oceans and sailing were remotely involved.

"The sea intrigues you," I say.

The edges of Ren's ears turn pink. "It does. I've read everything I can find on the topic. I'd give almost anything to sail the seas one day."

"Perhaps you shall."

"Not today." Ren moves on to the glass cases along the next wall filled with oddities from the ocean and old weapons. I gave these a cursory examination yesterday in hopes one might be Wizard's Bane. It was as fruitless as I expected.

Rusted chain links, a telescope, compasses, a globe, and even an old anchor rest inside. And many, many strange triangular devices—sextants.

"How on earth will we figure out which one?" I grumble.

Ren opens the case and begins to examine them one by one. "Some have rusted through and can't move. I doubt those are the right ones." He studies the compass design in the corner again. "I'd be willing to bet the one we want will match that. Maybe it will be gold, or will have the same filigree design."

Together we pore over the compasses and sextants, seeking something that resembles the ceiling compass. Nothing stands out to me.

But Ren squeaks as he moves aside sextants on the bottom level. "Look, Rosabel!" A faint outline mars the bottom of the shelf, but I'd never have noticed with all the debris on top. Ren pries the paneling on the shelf up carefully, revealing a secret compartment that holds a crumpled map. He frowns as he pulls it out. "Who would do such a thing to a map . . . ?"

A gleaming gold sextant tumbles out of the parchment, but Ren catches it with his nimble hands. Adrenaline ripples through me.

"What do you think it will do?" I ask.

"I hope it's the key we need to unlock that door. If this map is any indication" –he spreads the crumpled paper flat on a table– "then I believe I'm right."

The map isn't of the ocean; it features the night sky. It looks just like the ceiling in the library, right down to the compass points in the four corners. A drawing of the gold sextant lies near the northern compass point.

"Now that is a remarkable likeness," I say, unable to suppress a smile.

We return to the northern corner of the room and this time Ren goes first, scrambling up the ladder, quick as the monkeys we once saw in a traveling caravan. I crane my neck to see while he fiddles with the settings on the sextant. I can't make sense of it, but it clearly means something to him. Then he turns to the compass point where it juts out from the corner. I couldn't get it to budge, but he finds a way to fit the sextant onto it in just the right manner so that it clicks, then gives, and suddenly the panel above swings open.

I start up the ladder and Ren gives me a boost into the opening. I crawl through into a room far larger than I expected. It looks like it spreads across the entire library. Above me is only sky—the ceiling is a glass dome and covered with sparkling dew and stars. This room, too, is full of books. If the ones in the library proper are old, then these are ancient. They fill the shelves with titles on their spines that I can barely understand. A thick layer of dust covers everything. How long has it been since a human set foot in here? Gooseflesh breaks out on my arms.

If any place in the city has the information I need on the Wizard's Bane, this is it.

"Amazing," Ren says behind me.

"What do you think is in here? And who built it?"

"And why?" Ren adds.

Moonbeams stream down and light up the tomes like stars reflected back at the sky from a pond. Did my parents build this room or was it already here? Do they know it exists? And if they do, why have they never told me about it? I'll rule this city one day; shouldn't I know every nook and cranny in my castle?

"I wonder what they thought they needed to hide," Ren muses.

I wander toward the first table and run my fingers through the dust. It puffs, making me sneeze, but by then the cover is half cleared.

Magi Ministeria. Wizard's Ministerings.

My heart leaps into my throat. "I know why they hid these books. They're dangerous."

Ren frowns. "What do you mean?"

"These are spell books."

Any question of whether my parents knew about this room vanishes. Mama would faint from fright and then burn the library if she had any inkling these existed, and in our own home.

An awed silence passes over us, just as the moon ducks behind a patch of cloud, abandoning us to the darkness. I shudder. It has been a very long time since magic was forbidden in the realm. We're surrounded by the bones of a magical past. We all know the stories of how wizards came to be, but magic itself is older and even more cunning. One tiny error in a spell and it could go horribly awry. Of course there's hardly any magic hanging about, not like there once was. They say before the dragon riders transformed into wizards, before they became greedy, magic flowed in the waters, whispered in the air currents, and made the soil fertile with exotic plants.

I would have particularly liked to see the last.

"Are they safe to touch?"

I frown. I hadn't considered that. "I think so.Spell books are just books after all." I sound more certain of this than I feel. "Besides, not much magic is left to be conjured anyway. You can't just create magic, we have to use what already exists and transform it into a spell."

"A spell and its cost."

A chill runs over my shoulders until the moon sneaks back out from behind the cloud. "Yes, there is always a price."

"I wonder what the price will be for the Wizard's Bane?"

"Perhaps I will grow a tail. Would you still like me with a tail?" I try to shove away my fears and twirl around, pretending to have a tail.

Ren guffaws. "A princess with a tail? The commoners would revolt."

I punch him playfully on the arm. "Or perhaps you'll grow another head."

Ren sobers. "What if the price is something terrible? Worse than the wizard at our gates?"

I glance at the books, so well hidden here, probably lost even to my grandparents' memories, and take a deep breath.

"What choice do I have? Waiting under an invisible wizard's thumb is unthinkable." The memory of what Mama said about the wizard being terribly patient comes to mind in a cold rush. "He'll come for me sooner or later. We have to be rid of him once and for all."

Ren sighs, a weary acceptance of things beyond our control. "Let's see if we can find something that will help."

We decide the best possibilities are where we'd normally look last—in other words, the darkest corners of the hidden room. We divide them up and are soon coated in a layer of dust, and frustrated by lack of progress. Books about how to catch a dragon, or the origin of the various hybrid species (a spell gone awry, it turns out), how to make a potion only from mermaid scales, and other assorted useless things are all we can find. Soon the sun begins to peek through the clouds, brightening the dome over this room.

Then, as I am about to give up and call it a night, my hands clasp one small book in the farthest corner. It's bound in black leather with a cover etched with ink that only shows up in the shadows and fading moonlight, becoming invisible when it's struck by the first few rays of sun.

"Wait!" I say. "I think I have something."

The Origin of Wizards.

Ren reads over my shoulder just as the last vestiges of ink fade away, leaving only the black cover behind. My fingers tingle. "This one is special—I can feel it," I say. "If it has how they began, perhaps it will include how to end them."

Ren smiles, dust stuck to his chin. "Let's hope so."

I tuck the book into my pocket, and together we leave the hidden room behind.