I went over to my bag and pulled out my magic wand. "Want me to practice breaking us out?"

"Certainly, if we had more time," Maud said. "But I'm sure King Frederick has provided Peter with keys to our room, as well as to the princesses' quarters."

"Could they be any more obvious?" I scoffed. "And I can't believe Sloane didn't warn Jessaline about the food."

"It does seem to have slipped her mind, doesn't it? At least we can be sure that our efforts will be uninterrupted tonight." Maud laid Muffet's limp body beside Alfonso, then went over to the fire to stir the draught.

We heard someone unlocking the door and Peter entered. "Are you ready?"

"Come in and close the door," Maud told him. "Everyone needs to take three sips of this." She poured the draught into a glass and handed it him. He winced as he drank and then handed it to me.

It smelled sweet and flowery, but tasted bitter. Throat burning, I passed it to Maud, who took her sips and discarded the rest.

"So this will keep us awake?" Peter asked.

"Not just that. Look at yourself," Maud said with a grin.

He gasped. The draught had made him into a human chameleon in that his skin and clothing matched whatever background he stood against. It was eerie seeing his vague outline in the same pattern as the bed-curtains.

I glanced down, feeling giddy at not being able to see most of my body.

The outline of Maud was moving toward the door, an unsettling sight like watching a stream of smoke glide through the air. "Okay, I don't want any of us to get lost, so we'll need to hold hands. Peter, you lead the way."

He locked our bedroom door again at Maud's suggestion and then, joining hands, we glided down the corridor like a freakish three-headed specter.

We wandered through endless hallways, doorways, and stairwells, and I was beginning to wonder whether we were lost when Peter gave a hushed cry of triumph. We had arrived at a wing tucked into the lowest bowels of the castle, and I knew we had come to the right place because of all the shrieking and giggling going on behind the door. It definitely sounded like a dozen girls getting ready for a party.

"Peter, open the door slowly," Maud instructed the prince. "They won't hear you with all that racket."

In the dim torchlight, I saw the outline of Peter's hand reaching for the knob. There was an almost indiscernible click, and the door opened onto a richly furnished parlor. The voices were coming from a door on the other side of the room.

"Are they decent?" Peter quavered. I grinned, imagining the look on his face.

Maud went to check. "They're all dressed."

The princesses looked like a flock of colorful birds, decked out in the finest silk and jewels. Being my mother's daughter, I peeked at their shoes, which shimmered with newness beneath their gowns. I could tell their local shoemaker knew how to put together some decent footwear. Maybe not as well-made as Mom's, but a close second.

"Are we all ready?" Rosamond asked. "You two can do the honors tonight." She nodded at a pair of twins, who approached the largest of a set of frilly canopied beds lining the circular room. They each pressed one of the bedposts and the bed began to descend beneath the floor, moving aside to reveal a set of spiraling stone steps flickering with torchlight.

"So that's how they do it," Peter whispered.

"Hush," Maud warned. We waited for the last girl to climb down the winding stair before we followed.

At the bottom was a platform in the midst of a damp cavern. Icicles of rock stretched over us as far as the eye could see, all dripping with the wet. When Rosamond lit a torch, I nearly gasped at the enormity of the black lake before us. If I hadn't known better, I would have thought that we had reached the end of the world, where land had become a desert of dark water.

I couldn't see either of my companions and a panicked feeling rose in my throat. An invisible hand grabbed mine and I heard Maud whisper, "Look. That's where they're going."

My jaw dropped at the sight of the castle on the other side of the lake, which glowed an eerie gray-green.

"Get into any boat you can, and do not let the princess who is rowing it know that you're there," my trainer hissed. And then she was gone.

I looked around frantically. Each princess was stepping into one of twelve wooden boats tied to the platform. Rosamond walked around, using her torch to light lanterns dangling at the front of each boat. The lanterns had been painted green, which dimmed the firelight.

Rebecca, the youngest princess, was climbing into the boat nearest me. Quickly I hopped in behind her, taking care not to step on her dress. She didn't seem to notice anything as she sat down and held her oars at the ready.

"All right, girls. Let's go," Rosamond said, getting into her own vessel. I thought I spied the outline of Peter getting in behind her.

In unison, the twelve princesses began rowing across the black lake to the kingdom that awaited them on the opposite shore. They did so in silence, which was occasionally punctuated by a nervous giggle, but it made the trip all the more creepier. I looked up at the vast, spiked ceiling of the cave, wondering why anyone would build a castle in such a horrible, damp place.

One of the other princesses looked over at Rebecca. "What's the matter, little sister?" she teased. "Still a bit out of practice?"

"I don't know why, but my boat seems so heavy tonight," Rebecca complained, her little red silk arms straining to propel us forward.

I made a mental note to apologize later, if I got the chance, but I hadn't thought I would be that heavy. I glanced at Rosamond, who did seem to be panting a bit herself.

After what seemed like an age, we finally reached the shore. The princesses tied their boats to the platform and I took the opportunity to gaze up at the strange, glowing turrets and crenellations wrapped in tongues of slithering green smoke.

I thought of the other three castles I had seen in my limited travels: the one in Indigo, humble and homey, perfect for a small rural kingdom; Irisia Palace, sophisticated and grand; and Viridian Castle, perched on the mountains like a bigger version of one of its gargoyles.

But this one had an altogether different feel. It made me think of damp, slimy things untouched by sun.

"Oh, my arms," one of the twins complained. "I felt like I was rowing two people."

I looked eagerly at the boat she had just vacated and thought I saw it rock gently as someone invisible stepped out. Soon I heard Maud whispering my name nearby and I reached out for a cold hand I couldn't quite see.

"How was the trip? I heard Rebecca complaining and I knew you had to be with her."

"It was fine," I whispered back. "Where's Peter?"

"He must be up near Rosamond. Hopefully he doesn't trip and fall on his face."

I shivered. "What is this place? It gives me the creeps. Why would there be a kingdom down here?"

Maud's voice was uneasy. "I have a feeling that . . ."

She was interrupted by a deafening creak. The massive doors had opened to reveal a fleet of handsome, dark-haired princes dressed in flowing black capes. The leader wore a huge golden crown that reflected his cat-like smile.

"Welcome back, princesses," he said in a strangely accented voice, holding out an arm to Rosamond. "My lady, your beauty is as unique as that of a rose among many boulders."

"Did he just call us boulders?" one of the other princesses whispered. Her sisters shrugged.

I heard a distinct scoff from somewhere to my right, where there should have been nothing but empty space.

"I think we found Peter," Maud whispered, amused. Sure enough, when she reached out and touched his arm, he yelped. "Calm down, it's just us."

Rebecca spun around. "What was that?"

"I heard nothing, Princess," replied one of the princes with a suave smile.

My companions and I watched as the couples paired off and headed inside the castle.

"Was that Leo?" Peter sputtered. "He looks like he should be sleeping in a coffin with a bunch of garlic or something."

"Vampires don't like garlic," I reminded him, but I had to admit that he was right. Leo was definitely good-looking, but in a chalk-faced, hollow-eyed kind of way, which made me wonder why the princesses didn't seem to be more frightened. "Why do you think the girls aren't more afraid, Maud?"

"I wonder if they're not under some sort of . . . spell," Maud murmured, and the torches all around us seemed to flicker at the word.

The doors began to close and we rushed inside before they could shut us out. A knot of apprehension tightened in my belly when I realized that we were now locked in with the princesses and their nightmarish suitors. I stuck close to Maud and Peter as we came into a vast ballroom hewn from stone and lit only by candlelight. Along one wall stood floor-to-ceiling windows, through which I could see the night sky, a starless, moonless shroud of navy.

"That's not possible. We're underground," Peter said, bewildered. "This has got to be dark magic."

"I agree. There is almost certainly witchcraft at work here," Maud said grimly.

A windstorm of ghostly musicians leapt into action and the strains of a melancholy waltz filled the room. From the perimeter came hundreds, maybe thousands of shadow people who formed a smoky ring around the dance floor, like an audience of noblemen. They murmured and swayed to the music as the twelve couples whirled around.

Strange flowering trees appeared in each corner of the room. One of them blossomed close to where we stood and I saw that each glistening gold leaf was shaped like a large heart dripping a smaller one.

I heard a scuffle to my left and saw the outline of Maud's arm restraining Peter, who seemed to be trying to get to Leo and Rosamond.

"Just what exactly do you plan to do?" she hissed. "Fight him?"

"No, I was just going to trip him, but that's not a bad idea," Peter's voice replied. "He wouldn't be able to see me very well, would he?"

"Stay where you are," the fairy godmother commanded. "We only came to find out where the princesses go every night. Now we wait until we can report to the king."

Peter made an exasperated noise. "What are we going to say? 'Oh yes, Your Majesty, your daughters go underground every night to dance with a bunch of corpses.' He'll have no problem believing that."

"We could take something for evidence," I suggested. "Like a leaf from this tree."

"That's better than nothing," Peter grumbled, plucking a leaf off one of the low branches.

Intrigued, I plucked one myself. It felt like a smooth pebble in my hand. "This tree has gold leaves. That one over there looks like it has silver ones," I said, squinting across the room. "Maybe we should take a leaf from each."

"I'll be back," Peter said.

"Wait!" Maud cried, then sighed. "I lost him. I was going to have you go instead, Noelle, just to keep him from doing something stupid to Leo."

"He's certainly a lot braver when he's invisible," I observed. "So do you think these princes are vampires?"

"No, because this place reeks of dark magic and only witches have that. But they're not witches, either," Maud said thoughtfully. She was silent for a moment. "Tell me, Noelle. What kinds of creatures live in the mountains and have been known to align with witches?"

I racked my brains. "Well, we can definitely rule out dragons and dwarves." And then it hit me. "Goblins! They're goblins!" Watching the lanky princes spin their partners, I decided that it made perfect sense. "They live in a cave far from daylight. They've got a lake where they can get food. And the green glow of the castle . . . that's definitely goblin quartz. Nothing else shimmers like that."

"How do you know about goblin quartz?" Maud asked, surprised.

"Mom used it for a collection of sandals back in the day," I explained. "They weren't popular, though. Glowed too much in the dark and completely ruined the effect of ball gowns."

"I'm back," said Peter's voice nearby, which made us jump. "Got all four leaves right here in my pocket. I wonder how much longer they're going to dance?"

A new waltz begun, just as mournful and depressing as the first. I decided that if it were ever appropriate to dance in ball gowns at a funeral, this music would be perfect.

"And more importantly," Peter continued, "how much longer will this draught work?"

"We should be good for a couple more hours," Maud said.

"Well, I hope they don't stay that long," he grumbled, and I distinctly heard his stomach growling.

To get his mind off food, Maud got him up to speed with what we had been discussing about the princes possibly being goblins.

"Now, if only we can test the idea," I said.

"Well, actually, I think we can," my trainer affirmed. Her voice had a hint of mischief in it. Peter and I waited, wondering what she would come up with.