Chapter 1

My Rescue Operation Goes Very Wrong

The Friday before winter break, my mom packed me an overnight bag and a few deadly weapons and took me and Thalia to a new boarding school. We picked up my friend Anthony on the way.

It was an eight-hour drive from New York to Bar Harbor, Maine. Sleet and snow pounded the highway. I haven't seen Anthony in months, but between the blizzard and the thought of what we were about to do, we were too nervous to talk much. Except for my mom. She talks more when she's nervous. By the time we finally got to Westover Hall, it was getting dark, and she'd told Anthony and Thalia every embarrassing baby story there was to tell about me.

Thalia wiped the fog off the car window and peered outside. "Oh, yeah. This'll be fun."

Westover Hall looked like an evil knight's castle. It was all black stone, with towers and slit Windows and a big set of wooden double doors. It stood on a snowy cliff overlooking this big frosty forest on one side and the gray churning ocean on the other.

"Are you sure you don't want me to wait?" my mother asked.

"No, thanks, Mom," I said. "I don't know how long it will take. We'll be okay."

"But how will you get back? I'm worried, Perci."

I hoped I wasn't blushing. It was bad enough I had to depend on my mom to drive me to my battles.

"It's okay, Ms. Jackson." Anthony grinned reassuringly. He has gotten a haircut, so his long bangs were now shorter and stood up like a hot surfer's, tucked into a ski cap and his gray eyes were the same color as the ocean. "We'll keep her out of trouble."

My mom seemed to relax a little. She thinks Anthony is the most levelheaded, matured demigod ever to hit eighth grade. She's sure Anthony often keeps me from getting killed. She's right, but that doesn't mean I have to like it.

"Alright, dears," my mother said. "Do you have everything you need?"

"Yes, Ms. Jackson," Thalia said. "Thanks for the ride."

"Extra sweaters? You have my cellphone number?"

"Mom-"

"Your ambrosia and nectar, Perci? And a golden drachma in case you need to contact camp?"

"Mom, seriously! We'll be fine. Come on, guys."

She looked a little hurt, and I was sorry about that, but I was ready to be out of that car. If my mom told one more story about how cute I looked in the bathtub when I was three years old, I was going to burrow into the snow and freeze myself to death.

Anthony and Thalia followed me outside. The wind blew straight through my coat like ice daggers.

Once my mother's car was out of sight, Thalia said, "Your mom is so cool, Perci. And thanks for letting me stay with two."

"She's pretty okay," I admitted. "What about you? Don't you ever get in touch with your mom?"

As soon as I said it, I wished I hadn't. Thalia was great at giving evil looks, what with the punk clothes she always wears-the ripped-up jacket, black leather pants and chain jewelry, the black eyeliner and those intense blue eyes. But the look she gave me now was a perfect evil "ten." "If that was any of your business, Perci-"

"We'd better get inside," Anthony interrupted. "Gretel will be waiting."

Thalia looked at the castle and shivered. "You're right. I wonder what she found here that made her send the distress call."

I stared up at the dark towers of Westover Hall. "Nothing good," I guessed.

The oak doors groaned open, and the three of us stepped into the entry hall in a swirl of snow.

All I could say was, "Whoa."

The place was huge. The walls were lined with battle flags and weapon displays: antique rifles, battle axes, and a bunch of other stuff. I mean, I knew Westover was a military school and all, but the decorations seemed like overkill. Literally.

My hand went to my pocket, where I kept my lethal ballpoint pen, Riptide. I could already sense something wrong in this place. Something dangerous. Thalia was rubbing his silver bracelet, her favorite magic item. I knew we were thinking the same thing. A fight was coming.

Anthony started to say, "I wonder where-"

The doors slammed shut behind us.

"Oo-kay," I mumbled. "Guess we'll stay awhile."

I could hear music echoing from the other end of the hall. It sounded like dance music.

We stashed our overnight bags behind a pillar and started down the hall. We hadn't gone very far when I heard footsteps on the stone floor, and a man and woman marched out of the shadows to intercept us.

They both had short gray hair and black military-style uniforms with red trim. The woman had a wispy mustache, and the guy was clean-shaven, which seemed kind of backwards to me. They both walked stiffly, like they had broomsticks typed to their spines.

"Well?" the woman demanded. "What are you doing here?"

"Um…" I realized I hadn't planned for this. I'd been so focused on getting to Gretel and finding out what was wrong, I hadn't considered that someone might question three kids sneaking into the school at night. We hadn't talked at all in the car about how we would get inside. I said, "Ma'am, we're just-"

"Ha!" the man snapped, which made me jump. "Visitors are not allowed at the dance! You shall be eee-jected!"

He had an accent-French, maybe. He pronounced his J like in Jacques. He was tall, with a hawkish face. His nostrils flared when he spoke, which made it really hard not to stare up his nose, and his eyes were two different colors-one brown, one blue-like an alley cat's.

I figured he was about to toss us into the snow, but then Thalia stepped forward and did something very weird.

She snapped her fingers. The sound was sharp and loud. Maybe it was just my imagination, but I felt a gust of wind ripple out from her hand, across the room. It washed over all of us, making the banners rustle on the walls.

"Oh, but we're not visitors, sir," Thalia said. "We go to school here. You remember: I'm Thalia. And this is Anthony and Perci. We're in the eighth grade."

The male teacher narrowed his two-colored eyes. I didn't know what Thalia was thinking. Now we'd probably get punished for lying and thrown into the snow. But the man seemed to be hesitating.

He looked at his colleague. "Ms. Gottschalk, do you know these students?"

Despite the danger we were in, I had to bite my tongue to keep from laughing. A teacher named Got Chalk? He had to be kidding.

The woman blinked, like someone had just woken her up from a trance. "I...yes, I believe I do, sir." She frowned at us. "Anthony. Thalia. Perci. What are you doing away from the gymnasium?"

Before we could answer, I heard more footsteps, and Gretel ran up, breathless. "You made it! You-"

She stopped short when he saw the teachers. "Oh, Mrs. Gottschalk. Dr. Thorn! I, uh-"

"What is it, Ms. Underwood?" said the man. His tone made it clear that he detested Gretel. "What do you mean, they made it? These students live here."

Gretel swallowed. "Yes, sir. Of course, Dr. Thorn. I just meant, I'm so glad they made...the punch for the dance! The punch is great. And they made it!"

Dr. Thorn glared at us. I decided one of his eyes had to be fake. The brown one? The blue one? He looked like he wanted to pinch us off the castle's highest tower, but then Mrs. Gottschalk said dreamily, "Yes, the punch is excellent. Now run along, all of you. You are not to leave the gymnasium again!"

We didn't have to be told twice. We left with a lot of "Yes, ma'ams" and "Yes, sirs" and a couple of salutes, just because it seemed like the thing to do.

Gretel hustled us down the hall in the direction of the music

I could feel the teachers' eyes on my back, but I walked closely to Thalia and asked in a low voice, "How did you do that finger-snap thing?"

"You mean the Mist? Hasn't Chiron shown you how to do that yet?"

An uncomfortable lump formed in my throat. Chiron was our head trainer at camp, but he'd never shown me anything like that. Why had he shown Thalia and not me?

Gretel hurried us to a door that had GYM written on the glass. Even with my dyslexia, I could read that much.

"That was close!" Gretel said. "Thank the gods you got here!"

Anthony and Gretel gave each other a fist-pump. Thalia and I both gave her a hug and then I high-fived with her.

It was good to see her after so many months. She'd gotten a little taller and her hair looked more longer, and with a small ponytail on the back of her hair, but otherwise she looked like she always did when she passed for human-her amber hair with a few green streaks, like she dyed her hair, skinny jeans and sneakers to hide her soil-producing feet. She was wearing a black T-shirt that took me a few seconds to read. It said WESTOVER HALL: GRUNT. I wasn't sure whether that was, like, Gretel's rank or maybe just the school motto, and had her green whip strapped around her waist.

"So what's the emergency?" I asked.

Gretel took a deep breath. "I found two."

"Two half-bloods?" Thalia asked, amazed. "Here?"

Gretel nodded.

Finding one half-blood was rare enough. This year, Chiron had put the satyrs and Gretel on emergency overtime and sent them all over the country, scouring schools from fourth grade through high-school for possible recruits. These were desperate times. We were losing campers. We needed all the new fighters we could find. The problem was, there just weren't that many demigods out there.

"A brother and a sister, biologically related," she said. "They're ten and twelve. I don't know their parentage, but they're strong. We're running out of time, though. I need help."

"Monsters?"

"One." Gretel looked nervous. "He suspects. I don't know think he's positive yet, but this is the last day of term. I'm sure he won't let them leave campus without finding out. It may be our last chance! Every time I try to get close to them, he's always there, blocking me. I don't know what to do!"

Gretel looked at Thalia desperately. I tried not to feel upset by that. Used to be, Gretel looked to me for answers, but Thalia had seniority. Not just because her dad was Zeus, Thalia had more experience than any of us with fending off monsters in the real world.

"Right," she said. "These half-bloods are at the dance?"

Gretel nodded.

"Then let's dance," Thalia said. "Who's the monster?"

"Oh," Gretel said, looking around nervously. "You just met him. The vice principal, Dr. Thorn."

Weird thing about military schools: the kids go absolutely nuts when there's a special event and they get to be out of uniform. I guess it's because everything's so strict the rest of the time, they feel like they've got to overcompensate or something.

There were black and red balloons all over the gym floor, and guys were kicking them in each other's faces, or trying to strangle each other with the crepe-paper streamers taped to the walls. Girls moved around in football huddles, the way they always do, wearing lots of makeup and spaghetti-strap tops and brightly colored pants and shoes that looked like torture devices, and trust me, I would be caught dead wearing shoes like that (kind of literally). Every once in awhile they'd surround some poor guy like a pack of piranhas, shrieking and giggling, and when they finally moved on, the guy would have ribbons in his hair and a bunch of lipstick graffiti all over his face. Some of the older guys and girls looked more like me-uncomfortable, hanging out at the edges of the gym and trying to hide, like any minute they. Might have to fight for their lives. Of course, in my case, it was true…

"There they. Are," Gretel nodded toward a couple of younger kids arguing in the bleachers. "Bianca and Nico di Angelo."

The girl wore a flappy green cap, like she was trying to hide her face. The boy was obviously her little brother. They both had dark silky hair and olive skin, and they used their hands a lot as they talked. The boy was shuffling some kind of trading cards. His sister seemed to be scolding him about something. She kept looking around like she sensed something was wrong.

Anthony said, "Do they...I mean, have you told them?"

Gretel shook her head. "You know how it is. That could put them in more danger. Once they realize who they are, their scent becomes stronger."

She looked at me, and I nodded. I'd never really understood what half-blood's "smell" like to monsters and satyrs or even nymphs, but I knew that your scent could get you killed. And the more powerful a demigod you become, the more you smelled like a monster's lunch.

"So let's grab them and get out of here," I said.

I started forward, but Thalia put her hand on my shoulder. The vice principal, Dr. Thorn, had slipped out of a doorway near the bleachers and was standing near the di Angelo siblings. He nodded coldly in our direction. His blue eye seemed to glow.

Judging from his expression, I guessed Thorn hadn't been fooled by Thalia's trick with the Mist after all. He suspected who we were. He was just waiting to see why we were here.

"Don't look at the kids," Thalia ordered. "We have to wait for a chance to get them. We need to pretend we're not interested in them. Throw him off the scent."

"How?"

"We're three powerful half-bloods. Our presence should confuse him. Mingle. Act natural. Do some dancing. But keep an eye on those kids."

"Dancing?" Anthony asked.

Thalia nodded. She cocked her ear to the music and made a face. "Ugh. Who chose the Jesse McCartney?"

Gretel looked hurt. "I did."

"Oh my gods, Gretel. That is so lame. Can't you play, like, Green Day or something?"

"Green who?"

"Never mind. Come on."

Gretel yelped as Thalia grabbed her hand and led her onto the dance floor.

Anthony smiled.

"What?" I asked.

"Nothing. It's just cool to have Thalia's back."

Anthony had grown taller than me since last summer. He still wore his Camp Half-Blood bead necklace, and his new hair-style really looked more like...him: strong and smart. But it also made him look older.

"So…" I tried to think of something to say. Act natural. Thalia had told us. When you're a half-blood on a dangerous mission, what the heck is natural? "Um, design any good buildings lately?"

Anthony's eyes lit up, the way they always did when he talked about architecture. "Oh my gods, Perci. At my new school, I get to take 3-D design as an elective, and there's this cool computer program…"

He went on to explain how he'd designed this huge monument that he wanted to build at Ground Zero in Manhattan. He talked about structural supports and facades and stuff, and I tried to listen. I knew he wanted to be a super architect when he grew up-he loves math and historical buildings and all that-but I hardly understood a word he was saying.

The truth was I was kind of disappointed to hear that he liked his new school so much. It was the first time he'd gone to school in New York. I'd been hoping to see him more often. He was going to a boarding school somewhere outside New York City and Thalia and I were attending a boarding school in Brooklyn, close enough to Camp Half-Blood that Chiron could help if we got in any trouble. Because it was an all-girls school, and he was all the way in Virginia, I hardly ever saw him with only Thalia for company.

Of course, my mother happily took Thalia in as she got her well treated, which she once told she has never felt like she was home. We have this sort of hate-love relationship, like most sisters do, but she still see each other as friends, even if I sometimes douse her with water for calling me "Salt-for-Brains" and she sometimes shocked me when I called her "Hurricane Thalia". I could see how our relationship reflects our fathers really. At school, I had to tell everyone that Thalia and I are cousins, which was technically true.

"Yeah, uh, cool," I said. "So you're staying the rest of the year, huh?"

His face got dark. "Well, maybe, if I don't-"

"Hey!" Thalia called to us. She was slow dancing with Gretel, which made me want to laugh a little, and she looked like she wanted to die of embarrassment.

"Dance, you guys!" Thalia ordered. "You look stupid just standing there."

I looked nervously at Anthony, then he looked at the group of girls who were roaming the gym.

"Well?" I asked.

"Um…" Anthony rubbed his hands nervously. "Who should I ask?"

I scoffed as I punched him in the gut. "Me, Owl-Head." For once, I understood what Thalia was telling us.

So we went onto the dance floor, and I looked over to see how Thalia and Gretel were doing things Anthony put hand on my hips and he clasped my other hand like he was about to judo throw me. And I could be seeing things, but he looked like he was blushing.

"I'm not going to bite," I told him. "Honestly, Anthony. Don't you guys have dances at your school?"

He didn't answer. The truth for me was that I did, but I never, like, actually danced at one. I was usually one of the girls playing basketball in the corner, and I guess we were both on the same boat.

We shuffled around for a few minutes. I tried to concentrate on little things, like the crepe-paper streamers and the punch bowl-my hands were sweaty and probably gross, and Anthony kept stepping on my toes.

"What were you saying earlier?" I asked. "Are you having trouble at school or something?"

He pursed his lips. "It's not that. It's my dad."

"Uh-oh," I knew Anthony had a rocky relationship with his father. "I thought it was getting better with you two. Is it your stepmom again?"

Anthony sighed. "He decided to move. Just when I was getting settled in New York, he took this stupid new job researching for a World War I book. In San Francisco."

He said this the same way he might say Fields of Punishment or Hades's gym shorts.

"So he wants you to move out there with him?" I asked.

"To the other side of the country," he said miserably. "And half-bloods can't live in San Francisco. He should know that."

"What? Why not?

Anthony rolled his eyes. Maybe he thought I was kidding. "You know. It's right there."

"Oh," I said. I had no idea what he was talking about, but I didn't want to sound stupid. "So...you'll go back to living at camp or what?"

"It's more serious than that, Perci. I...I probably should tell you something."

Suddenly he froze. "They're gone."

"What?"

I followed his gaze. The bleachers. The two half-blood kids, Bianca and Nico, were no longer there. The door next to the bleachers was wide open. Dr. Thorn was nowhere in sight.

"We have to get Thalia and Gretel!" Anthony looked around frantically. "Oh, where'd they dance off to? Come on!"

He ran through the crowd. I was about to follow when a mob of girls got in my way. I maneuvered around them to avoid getting the ribbon-and-lipstick treatment, and by the time I was free, Anthony had disappeared. I turned a fall circle, looking for him or Thalia and Gretel. Instead, I saw something that chilled my blood.

About fifty feet away, lying on the gym floor, was a floppy green cap just like the one Bianca di Angelo had been wearing. Near it were a few scattered trading cards. Then I caught a glimpse of Dr. Thorn. He was hurrying out a door at the opposite end of the gym, steering the di Angelo kids by the scruffs of their necks, like kittens.

I still couldn't see Anthony, but I knew he'd be heading the other way, looking for Thalia and Gretel.

I almost ran after him, and then I thought, Wait.

I remembered what Thalia had said to me in the entry hall, looking at me all puzzled when I asked about the finger-snap trick: Hasn't Chiron shown you how to do that yet? I thought about the way Gretel had turned to her, expecting her to save the day.

Not that I resented Thalia. She was cool. It wasn't her fault her dad was Zeus and she got all the attention….Still, I didn't need to run after her to solve every problem. Besides, there wasn't time. The di Angelos were in danger. They might be long gone by the time I found my friends. I knew monsters. I could handle this myself.

I took Riptide out of my pocket and ran after Dr. Thorn.

The door led into a dark hallway. I heard sounds of scuffling up ahead, then a painful grunt. I uncapped Riptide.

The pen grew in my hands until I held a bronze Greek sword about three feet long with a leather-bound grip. The blade glowed faintly, casting a golden light on the rows of lockers.

I jogged down the corridor, but when I got to the other end, no one was there. I opened a door and found myself back in the main entry hall. I was completely turned around. I didn't see Dr. Thorn anywhere, but there on the opposite side of the room were the di Angelo kids. They stood frozen in horror, staring right at me.

I advanced slowly, lowering the tip of my sword. "It's okay. I'm not going to hurt you."

They didn't answer. Their eyes were full of fear. What was wrong with them? Where was Dr. Thorn? Maybe he'd sensed the presence of Riptide and retreated. Monsters hated celestial bronze weapons.

"My name's Perci," I said, trying to keep my voice level. "I'm going to take you out of here, get you somewhere safe."

Bianca's eyes widened. Her fists clenched. Only too late did I realize what her look meant. She wasn't afraid of me. She was trying to warn me.

I whirled around and something went WHIIISH! Ain exploded in my shoulder. A force like a huge hand yanked me backward and slammed me to the wall.

I slashed with my sword but there was nothing to hit.

A cold laugh echoed through the hall.

"Yes, Persephone Jackson," Dr. Thorn said. His accent mangled the J in my last name. "I know who you are."

I tried to free my shoulder. My coat and shirt were pinned to the wall by some kind of spike-a black dagger-like projectile about a foot long. It had grazed the skin of my shoulder as it passed through my clothes, and the cut burned. I'd felt something like this before. Poison.

I forced myself to concentrate. I would not pass out.

A dark silhouette now moved toward us. Dr. Thorn stepped into the dim light. He still looked human, but his face was ghoulish. He had perfect white teeth and his brown/blue eyes reflected the light of my sword.

"Thank you for coming out of the gym," he said. "I hate middle school dances."

I tried to swing my sword again, but he was just out of reach.

WHIIIISH! A second projectile shot from somewhere behind Dr. Thorn. He didn't appear to move. It was as if someone invisible were standing behind him, throwing knives.

Next to me, Bianca yelped. The second thorn impaled itself int the stone wall, half an inch from her face.

"All three of you will come with me," Dr. Thorn said. "Quietly. Obediently. If you make a single noise, if you call out for help or try to fight, I will show you just how accurately I can throw."