Summary: Percy, Annabeth, Thalia, and Nico are sent to Hogwarts to help the wizards in their ongoing war with Voldemort. But Harry suspects that they're more than just exchange students. Can the demigods keep their cover as wizards, or will it be blown by the Golden Trio?

Disclaimer: Me no own Percy or Harry. I never have and never will. Period.

Chapter 1: We learn Chiron Has a Counterpart and Meet Percy's Twin (sorta)

Percy's POV

Chiron called me, Annabeth, Nico, and Thalia (who was at camp for some strange reason) into the Big House. We sat down in the Living Room and waited for Chiron to start talking. He paused, gathering his thoughts.

Chiron took a plunge. "I'm not going to beat around this bush with this. I'm just going to go straight to the point. This may come as a shock to you, but there are such things as wizards in this world."

There was mixed reactions. Annabeth scowled, probably annoyed that she hadn't known about this before. Thalia looked calm, like this sort of thing happened everyday. I was ready to implode from the fact that there are wizards, as if Greek gods aren't enough. Like, those people who wear pointy hats and way black sticks around. To think that I was strange.

Nico was the first to speak. He looked downright murderous. "I hate those wizard dudes. Always trying to cheat or avoid death. They cause so much paperwork and migraines."

"Wait a sec," I said, leaning forward. "You know about these... wizard people, or whatever?"

Nico rolled his eyes. "Well everybody has to die at some point," he said, like it was obvious. "Except for the Tom dude, and that guy who finally died a couple of years ago, what was his name? Oh yeah, Nicholas Flamel, and Albus..." he trailed off.

I turned to Thalia. "What about you? You don't seem surprised about this."

Thalia waved her hand casually. "Oh, we had a witch a couple of years ago join the Hunt. She died in the Titan War."

"Okay," I responded. "So you two have known about wizards but not told anyone."

My two cousins looked affronted. "We're not the only ones. You can't expect the Hecate cabin to not know about their mother's little pet world," Thalia said.

Chiron broke in. "Yes. Hundreds of years ago, Hecate blessed a number of mortals with the gift of magic. Since then, those mortals have grown and thrived, becoming more and more powerful. There are several wizarding schools located across the world. The closest one is in Salem, Massachusetts, near the..." he trailed off, but quickly continued, "...But the most famous one is in Scotland. Now, many years ago, one mortal took his powers too far. He became evil and tried to take over the world. He believed that only purebloods- wizards who's lineage came from Hecate's first blessed mortals- should be able to use magic. There was this big ongoing war, and Voldemort was killed. But he didn't die."

"Like monsters," I noted.

Nico nodded. "But waaaaaay more annoying." I didn't really understand, but didn't press matters, seeing as Nico looked really pissed.

Chiron continued. "Now he's back and at 'em. My old friend, Albus Dumbledore-"

"Who should have died, like, a million years ago!" Nico broke in.

"Who the heck is named Bumblebore?" Thalia asked, confused.

Chiron sighed, slightly annoyed at the interruptions. "Dumbledore, not Bumblebore. But anyways, my friend Albus has asked for help. He fears a battle, if not the entire war, soon. He has requested for more forces. We have agreed that you four are enough reinforcements."

"So what are we supposed to do?" Annabeth inquired curiously. Didn't anybody ever tell her that curiosity killed the cat? Apparently not.

"You four will be attending Hogwarts School of Witchcraft and Wizardry."

Thalia, Nico and I snorted at the name of the school. "What is that, a skin disease?" I asked, barely controlling my laughter.

Chiron took a deep breath and ignored my outburst. "You will be posing as students learning the art of wizardry. Important: you must not let them know you are demigods. I repeat, do NOT let them know. I have talked with Albus, and you will be transfer students from Salem. Don't worry about the magic- Hecate has agreed to bless you, thank the gods. Now, there is a group of three students, commonly known as the Golden Trio. They have a tendency for getting in trouble. Like you. Watch them and make sure they don't get into dangerous trouble."

"Such as?" Thalia asked.

"Such as fighting Lord Voldemort alone, or something along the lines of that."

We nodded to show we understood.

Chiron pulled out a piece of paper. "According to Albus, you must go to Little Whinging and find a Squib, or a non-magical person who had magical parents, and ask her for directions to Number Twelve, Grimmauld Place. That's where you will be staying for the rest of the summer, until school begins. All supplies you will need will be found there."

Annabeth frowned. "Why can't we just go straight to this Grim place?"

"Apparently, this place is very important, and the location is too secret to be put on paper. I think that's about it, but if you have any questions, just ask the professors. They have been told that you are demigods, not wizards."

"When are we leaving?" I asked.

"Immediately, actually. Annabeth and Percy, your families have been informed. Sally wanted me to give you a message, Percy."

"Oh, yeah?" I asked, wondering what she possibly wanted to tell me.

"Don't die, otherwise she'll kill you. Seems a little redundant, if you ask me."

"How are we getting to England, or wherever we're going?" Annabeth asked dubiously.

"Not by plane, please not by plane," I shivered.

"Ditto," Thalia said, and Nico nodded in agreement. "And please not by boat, either."

"I can get us there, guys," Nico spoke up, receiving doubtful looks from the rest of us. "What? I've gotten better over time."

Thalia and I shared a look, but in the end, we agreed.

"Oh, Nico, can I talk to you for a minute, please?" Chiron said just as we were about to leave. Nico hung back as the rest of us walked into the bright sunlight.

Harry POV

I followed Dudley as we made our way back to number four, Privet Drive. I hung back a bit as we neared the shortcut that would lead us to Wisteria Walk. Up ahead, I noticed four teenagers sitting on a low garden wall. Two teens, a boy and a girl both dressed in black, seemed to be arguing. They saw me nearing them, and the two stopped arguing.

"Excuse me, sorry to bother you, but do you know if we're anywhere near Privet Drive?" The punk girl asked. I didn't realize she was talking to me, so I made myself look like an idiot, looking around to find out who she was talking to. When I realized the question was directed to me, I blushed and cleared my throat. "Um, yeah, that's actually where I'm heading. You can follow me if you want." I realized that they could be Death Eaters, but by then, it was too late.

The younger goth boy turned to the girl. "Ha! I did take us to the right place! You just didn't believe me!"

"Well, if you hadn't been such an idiot, we could've asked for directions before, and we wouldn't have been wandering around in the heat for the past hour!" the girl retorted.

"But we didn't need directions! If you'd trusted me, we could have solved this without confirming the fact that we are in the right place!"

"Well, seeing what happened last time-"

"Shut it, you two!" the blond girl cut in. The girl turned to me. "Sorry about that. I would say they're not usually like this, but they are. Sadly." I realized that they all had American accents. "But anyway, can you point us in the direction of Privet Drive?"

"Um, sure," I responded. "But first, why do you want to go there?" I got the feeling that they weren't Death Eaters, otherwise they would have killed me by now. That didn't mean I couldn't be suspicious, though.

"We're looking for an old lady," the last teen, a boy said. I inspected him more closely. He kind of looked like me, if you added a lightning scar and glasses. We both had unruly black hair and green eyes, but his were more sea green than emerald green. That was pretty much where the similarities ended, though. He was tall, tanned, and well built, unlike me. His clothes actually fit, unlike my hand-me-downs. The blond girl smacked the back of his head.

"We don't know that, Seaweed Brain! She could be young for all we know!"

"Er, anyways, we should go. I'm supposed to be walking with my cousin right now. You guys coming?" They nodded and stood up. I raced to catch up with my stupid git of a cousin, Dudley.

The four Americans hung back as we went through the shortcut. They seemed nervous about something. They kept looking around. Their hands were straying to either a wrist, a pocket, or a hand.

Dudley started to taunt me. "You think you're so brave, don't you? Unlike at night."

"This is night," I pointed out. "When it goes all dark like this."

I heard a snicker from behind me. "Sarcastic, too. Are you sure you don't have a secret twin, Kelp Head," one of them joked.

Dudley continued to taunt me. "I've heard you at night. 'Don't kill him! Please don't kill him! Dad, help me!'" He said in a fake high-pitched voice. I growled but more quiet laughter erupted from behind me.

"And he talks in his sleep just like you! Squirtle, I think we've found your soul mate!"

"Shut up, you two," another one muttered.

All of a sudden, the street went dark. There was a rush of cold air. Dudley started whimpering, complaining that I was the one making it dark, and that he'd tell Uncle Vernon. However, I was completely befuddled. Even the stars seemed to be blacked out. I couldn't see anything, not even when I put my hand in front of my face.

There was another rush of freezing cold air, and I lost all happiness. I knew this feeling- it was dementors. But what were dementors doing in Little Whinging? I remembered the four Americans behind me. "Get down!" I yelled in their general direction. "Cover your mouths! Don't let them get you!"

A dementor swooped in, headed straight for me. I tried to summon a Patronus, but there were no happy thoughts in my head. I tried twice and failed. Then I heard something I didn't think I'd ever hear.

Laughter.

It was one of the boys, laughing hysterically. It cleared my mind long enough to summon a real Patronus. The stag drove right into the dementor. The dementor fled. Then I noticed another. It was prying Dudley's clamped hands off his mouth. "Hey!" I yelled at the Patronus. The dementor leaned over Dudley's now exposed mouth. The stag was too slow.

Then one of the American boys walked forward calmly, right up to the dementor. The dementor straightened up to look at its new prey.

"Get out of here," The goth boy growled quietly. "NOW!" The dementor turned and fled. The air was warm once again, and the streetlights flickered back on. I turned to see the other three Americans staring at the goth one.

"What?" he asked, unperturbed by the fact that he almost just lost his soul.

I thought that they would ask their friend how he did it, but instead the punk girl said disbelievingly, "Did you just laugh?"

A bit of color crept into the younger boy's cheeks. "Maybe."

The others looked shocked. "Behold!" the other boy cried out. "The day in which di Angelo laughs!"

"Shut up," 'di Angelo' muttered.

A low moan brought me back to reality. Dudley was still on the ground, covered in dirt. He was alive, which was all I cared about. There was a shuffling of footsteps, and old Figg arrived.

She was scowling and muttering under her breath. "That old scoundrel! Leaving when he wasn't supposed to, and looked what happened! Dementors! Here, in Little Whinging! Oh, what will they say? I hope Dumbledore gives him a piece f his mind!"

"Wait a second," I said. "You know Dumbledore?"

"Why of course!" the old lady shrieked. "Who doesn't know Dumbledore?"

"You're a witch?" I asked, dumbdounded.

"No! Of course not! I'm a Squib, and Mundungus knows that perfectly well, yet he goes off to see about some business! Lucky I had Mr. Tibbles on the case."

At the mention of a Squib, the Americans straightened up.

"See! I told you she was old!" my look-a-like said.

The blond slapped his arm. Ms. Figg turned to face them. "Who are... ah, the Americans. Dumbledore told me you would come looking for me. Well, we best get Potter here home first, before I answer your question. Come along."

Dudley hadn't moved, and it was obvious that he wasn't going to anytime soon. I mentally groaned at the though of having o carry him.

My look-a-like must have been thinking along the same lines, because he came up to me and offered to help carry the walrus-sized cousin. We slowly made our way to number four, Privet Drive. Ms. Figg insisted that I keep my wand out.

When we got to the garden wall, she left me, and the Americans followed her. I made my way up to the front door and turned around, wanting to ask Figg something. But she was gone, as was the other four teenagers. All that was left was a rush of cold air.

Dun, dun, dun! How'd you like it? This is my first crossover, so I'd appreciate constructive criticism.

Just so you know, the demigods have their own nicknames for each other. Annabeth uses Seaweed Brain for Percy, Pinecone Face for Thalia, and Death Breath for Nico. Percy uses Wise Girl for Annabeth, Pinecone Face for Thalia, and Zombie Dude for Nico. Thalia uses Owl Head for Annabeth, Kelp Head for Percy, and di Angelo for Nico. Nico uses Wise One for Annabeth, Squirtle for Percy, and Sparkles for Thalia.

Review, please!

Silver out.