If there's anything I've learned as a half-blood, it's control. We control our ADHD by learning to fight, we get perfect control of our bodies. If you're me, you get controlled by every god or immortal ever to cross your path. I've seen it all. But no matter the experience, no matter what gets thrown at me, I've always been able to control my own mind. But today, that was about to change.

It all started one morning when I was out overseeing some new-camper training. Kids were sword fighting, throwing spears and javelins, and launching arrows at straw dummies. A Hephaestus girl was throwing a shield for my hellhound, Mrs. O'Leary. I was dueling three young Apollo kids at once. Chiron says it's good training for everyone involved, but I still thrashed them easily. Apollo may be good at archery, but they're rubbish sword fighters.

"Keep your guard up, Trevor!" I yelled as I smacked him in the shoulder with the flat of my blade. He rubbed the offended area and I tapped the other shoulder. "And don't ever tend to an injury while there's still an enemy!" A girl, Marlene, rushed me from the side. Rather than blocking her sword, I jumped back. She stumbled forward, not meeting the expected resistance, and I brought Riptide up to rest gently on her neck. "Don't let momentum take away your balance. Stay in control," I told her, pulling my sword away to meet the next attack. I was about to swing at the third camper, Miranda, when I heard someone calling my name.

"Percy! Percy?" Travis Stoll ran into the arena. He bent over, catching his breath, then turned to me. "Percy, message from the Big House."

I disarmed Miranda with a neat trick I learned from Luke my first day here. "Keep practicing," I told them, capping Riptide and sticking it back in my pocket, now a ball point pen. "First one to figure out how that works gets off KP for a week." Being head of the Poseidon cabin has its advantages. The three kids jumped into action as I jogged over to Travis.

"What's up?" I asked him.

"Chiron wants to see you," he told me. "They didn't tell me why."

I nodded. I saw Chiron almost every day, but usually if he wanted to talk to me, he'd come down to the arena. This had to be big.

"Thanks Travis, " I said, heading for the door. "I'll be there as soon as I can."

Annabeth was waiting for me on the porch of the Big House. Her face was extremely grim.

"Took you long enough," she greeted me.

"Nice to see you too." I gave her a quick kiss on the cheek. "So what's going on?"

"Come in and see," she answered, although she was smiling. We went into the game room that also doubled as our meeting area. Chiron and Mr. D were sitting around the ping pong table playing two hands of pinochle each.

"Ah, excellent!" exclaimed Mr. D, tossing us each a stack of cards. "Sit down and play."

Annabeth shook her head. "Mr. D," she began, setting down the cards, "I really don't think-"

"Nonsense, Annabel," he blustered, drowning out the rest of her sentence. "There is always time for pinochle. Don't you agree?" he added, turning to Chiron. A light flickered in his eyes that I knew only too well. It usually meant Agree with me or I'll turn you into a porpoise. That sort of thing.

"Actually, sir," Chiron said delicately, "I do think we have rather more important matters to be dealing with."

Annabeth and I braced ourselves for the explosion, but Dionysus merely sighed.

"I suppose you might be right," he grumbled. He waved his hand and the cards disappeared. In their place was the newest edition of Wine Enthusiast. The god buried his nose in the magazine, seemingly losing all interest in us. Chiron hid a smile.

Annabeth cleared her throat. "Chiron, what exactly are we here for?"

I raised an eyebrow. Usually Annabeth knows this sort of thing long before I do. Apparently we were both in the dark.

"Ah yes," Chiron said, rising out of his wheelchair. I have never been able to figure out how he fits an entire horse body into that tiny chair. The Hephaestus kids might know. "Come with me, children."

He led us up the stairs to the second floor of the Big House, his hooves clopping on the wooden stairs. We went down a short hallway to a wooden door. Chiron took out a key from his saddlebag and unlocked it. I didn't have enough time to wonder what they were keeping up here that needed to be locked in before we found ourselves in a cozy little bedroom. And sitting on the bed was -

"Katie Gardner?" I asked, puzzled. "What're you doing here?"

Katie stood up and turned toward us. "Hello Percy, Annabeth," she said, smiling. "How are you today?"

"Just fine, thanks," Annabeth answered cautiously. "Is everything alright?"

"Absolutely. Perfectly. I've never been better." Her expression was perfectly pleasant, but something seemed...off. I turned to Chiron.

"Why is she here?" I demanded. "What's wrong with her?"

"One of her cabinmates brought her in," he told me. "Evidently they were out in the forest looking for a rare plant, they got separated, and when they found her, she wasn't acting the same. As for what's wrong with her, well."

He gestured me closer. "Look at her eyes," he said quietly.

I stepped forward and peered into Katie's dark brown eyes. She stared back at me quizzically.

"What's the matter, Percy?" she asked. As she spoke, I saw it: for a split second, her eyes flashed red.

I jerked back, glancing over at Annabeth, wondering if she'd seen it as well. Her ashen face was all the answer I needed.

"What was that?" I asked Chiron, backing away. I felt my hand straying to my pocket where I kept Riptide and quickly crossed my arms. No matter what was wrong with her, this was still Katie, still my friend. I wasn't about to pull a sword on her, even if the hairs on the back of my neck were screaming at me to do something.

Chiron gave me a long, indecipherable glance, then cantered towards Katie.

"My dear, what is your message?"

Before I could ask what he meant, Katie stood up, sauntering over to stand in front of him. Her expression was cruel and mocking, and not at all like her. Her eyes flashed red again.

"We have come," she said, smiling at him as if this were a perfectly normal conversation. "We seek the power of the Chosen One, the most powerful. He will be taken. He will be ours."

"Well that's ominous," I said, trying to keep my voice light. But Annabeth turned to Chiron, furious.

"'He will be taken'," she repeated, glaring at him, her grey eyes stormy. "So you brought him right to them? Right into their hands?"

"We needed the information," Chiron replied, his voice level, although his tail was swishing back and forth. "That's all she will say on the subject, over and over again. I believed that bringing in a new stimulus might trigger something else, something we could use."

"Um, not to be rude," I jumped in, "but what is she talking about? The Chosen One?"

Chiron and Annabeth both looked at me like I was an idiot.

"Oh," I said, the penny dropping. "You mean me. I'm the Chosen One."

"The Chosen One has identified himself. The rest will be called," Katie said. It was the matter-of-fact way she said it that really creeped me out. The Katie Gardner I knew was sweet and gentle - nothing like the person that stood before me.

"The others?" I asked her. "What others?"

Katie closed her eyes, a look of exhilaration filling her face. "My family," she whispered. "My family is coming. Soon, so soon, they will be here. And you," she said, turning to me, her voice matter-of-fact. "You will come with us."

She walked towards me, arms outstretched, as though ready to grab me then and there. I reached for Riptide, but Annabeth grabbed my arm.

"Percy, no!" she cried, yanking me towards the door. "Just get out, Katie might still be in there!"

I hesitated for a second, then let Annabeth pull me along. We dashed down the hall, Chiron cantering after us and slamming the door behind him. We didn't stop 'til we reached the game room.

Mr. D glanced up from his magazine. "Ah. Back from your little experiment, are we? Well Pedro? Annie? Satisfied? Learned all you could?"

"Sir, you are being unkind," Chiron said reprovingly.

"Blast that," Dionysus said dismissively. "I got sent here to train them, not be kind to them." He buried his nose in his magazine, staunchly ignoring us.

"Chiron, what was that?" Annabeth asked. "I've never seen anything like it, never read of anything that can do that? Is Katie a monster now? Possessed? Some kind of spirit? Or maybe-"

"All good guesses, Annabeth," Chiron said gently, "but I'm afraid I just don't know. I've never encountered such a thing either, in my travels or my readings. That's why I called you here," he said to me. "I was hoping she might give something away."

"Well?" I asked. "What did you learn?"

Chiron sighed. "Not as much as I'd like to," he said. "But some, yes. I must consult with my brethren. Perhaps they have heard of such a thing."

Chiron is the most civilized centaur I've ever met, and I've actually met quite a few. Most of his relatives, the Party Ponies,are complete nut-jobs, although they do come through in a pinch. I was skeptical that they would know anything, but Chiron seemed to think so.

"You two get going," he said to us. "Keep your eyes open. We have no idea what this might be."

We nodded and headed out of the room.

"Don't forget," Chiron called after us. "Capture the Flag tonight!"