This is my first crossover… It is mainly about PJO but there will be more Harry Potter coming soon in the later chapters. You know how I got the title? Demigods from PJO and Half-bloods from Harry Potter… Harry is a half-blood and Percy is a demigod. Most of the story will be from Allegra's POV but I will switch it around. It takes place after The Last Olympian so Percy already fulfilled the First Great Prophecy, but Harry has not fulfilled his. Harry is in the same year as Allegra and Alina.

Disclaimer: I don't own PJO or Harry Potter. I do own Allegra, Alina, Dinnie, and anything not recognized from the books unless stated otherwise. This will be the only disclaimer for the whole story.

I'd prefer only constructive criticism but any review is accepted by me. Also, if I messed up with the layout or something, please tell me and I will fix it as soon as possible.

At the end of each chapter, I will add any additional character info you might need to know.

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Allegra's POV
After our 3rd year in Hogwarts in the middle of summer, my mother told my twin Alina and I that we would be moving to the United States of America. More specifically, we would be moving to Manhattan, New York but will continue our education at Hogwarts during the year. Going upstairs to the room we both shared, we began to pack our trunks. I put my screech owl Talwn into his cage then began to fold my Ravenclaw robes, textbooks, and wizard contraptions. Alina also folded her Ravenclaw robes, books, and belongings then stuck her eagle owl Edgar into his cage. Both of us then grabbed our Firebolts and put them into the Quidditch compartment in our trunks before shrinking them to fit inside our zippered jacket pockets.

Both of us then dragged out our few muggle clothing items then changed for a long plane ride. I put on some dark denim capris, a red tank under a stretchy silver lycra tank then put on a black leather aviator jacket before putting on some black Nike sneakers and black leather fingerless gloves. My twelve inch sycamore wand with a dragon heartstring core was slipped into a wooden wand case before being tucked away into my special wand compartment inside my jacket. Turning to my twin, I saw we were almost identically dressed. Alina wore a dark denim miniskirt, a silver tank under a stretchy purple lycra tank before wearing her dark brown aviator jacket, black fingerless gloves, and black sneakers. Her twelve inch sycamore wand with a string of unicorn hair was stowed away in her compartment.

Both of us turned and walked downstairs where we found our mum putting concealment charms and other charms to protect this house. We would eventually return. Mum grabbed her trunk and shrunk it then changed into muggle clothing before we grabbed the green powder and used the floo network. We were of to Manhattan!

Alina and I went first arriving in the living room of our new apartment. Mum came crashing through the fireplace right after. "Mum…" I trailed off as I glanced around the tiny but neat apartment. "Is this our new home?"

Mum laughed a throaty laugh. "Yes, Allegra; this is our new home. We will only return to our other house before Term starts in the Fall. Until then, we'll be living here every summer! Isn't that nice?"

I just nodded solemnly before turning to Alina. "Let's go organize our room. Maybe use that spell to make it larger."

Alina and I turned and passed the kitchen before we made way into a small room, adjacent to the master suite. There were two futons on the floor both near the tiny window which enabled us to get fresh air. It took us an hour to organize our room so it could accommodate us with a lot of workspace. Taking a break we decided to go meet the neighbors.

Alina and I walked through the hall until we came to another door. We rang the doorbell then waited until a black haired and green eyed boy; very much like Harry Potter, greeted us. "Hello!" we said in a French/British accent. "We just moved into the apartment across the hall… I'm Allegra di Cipriano and she is my younger twin Alina di Cipriano. We came from Britain."

The older boy looked at us for a moment with a grimace then sniffed the air slightly. "Why don't you come in for awhile? I have to get something." The boy led us to the family room where there was a couch in which Alina and I sat. "Mom!" yelled the boy. "Our new neighbors are over!" With that the green eyed boy left.

Percy's POV
With a sniff of the air, I could tell the girls were not normal humans, they smelt funny, like they reeked of death. Sniffing the air once more I thought, definitely like death… Oh my gosh! It can't be!

I fumbled in my pocket for a golden drachma. My pockets were empty except for my pen Riptide. I then opened my closet which was quite messy till I found the latest pair of pants I wore at camp. There! Found ya!

With the drachma in hand, I slowly ever made my way to the tiny bathroom that was adjacent to my mother's office. Turning on the hot water in the sink and using the mirror as a reflective object, I created mist with a faint rainbow. Tossing the drachma into the mist I said, "Oh Iris goddess of the rainbow, please accept my offering; Chiron, at Camp Half-blood." The mist quickly formed so that a reflection of Chiron our camp counselor was easily seen. "Chiron!" I yelled. The centaur turned around with Annabeth, Grover, Thalia, and Nico. "I sense something really strange near my apartment. Earlier today, two twins and their mother moved into the apartment next door to mine. Queer huh? Both of them reek of death! Just like… Nico!"

"There are some more?" complained Mr. D as I heard his voice in the background. "Leave them, maybe they'll die." He continued to read his wine magazines and sip diet Coke.

"Let them die?" I asked exasperated. "We have a war coming in a few years the Second Great Prophecy will start; who knows when? We need all the half-bloods we can get!" I ranted on emphasizing the words need and war. "Especially if those two might be one of the prophesized seven!"

Chiron turned to Annabeth. "You and Nico go to Percy and investigate. He is right; we do need all the half-bloods we can get."

"Thanks Chiron!" I said as I disconnected the Iris Message and walked back to the living room.

Alina's POV
Allegra and I noticed that whatever that boy went, he was creating such a ruckus. His mum seemed very nice, and gave use blue lemonade and cupcakes. They were so good though I couldn't stop eating enough till Allegra tapped me on the shoulder. "You don't want to get too fat you can't fit into your Quidditch robes…"

She was right. I kind of ate too much. I wasn't fat nor was I slim, just average. My sister always says that we have a slender figure. Me slender? I thought. No way! My sister is the super slender/athletic one and she even has toned muscles and a faint six-pack on her abdomen! I'm the one that has a bit more fat… but has more curves.

I stopped eating till the boy came back and the doorbell rang. At the door, there was a blonde haired girl with gray eyes, about the same age as the green eyed boy, and there was a younger boy that was about our age. Something is not quite right… I thought. The younger one is so similar to us! I tapped my sister's leg and gave her the Eye.

Allegra's POV
With the tap and the Eye Alina gave me, I turned and gasped. The younger boy was almost identical to us! We had the same hair, eyes, clothing preferences… even the way we scowl!

"Who are you people?" I barely muttered as I saw a black iron sword at the younger boy's side. "What's happening?"

Alina grasped my hand and we squeezed. Both of us almost wanted to drag our wands out and say, Expelliarmus. "I'm Percy Jackson and this is Annabeth Chase and Nico di Angelo," said the green eyed boy.

Annabeth came in front of us and asked, "Do you believe in the Greek Myths?"

I turned to Alina then mumbled, "I don't remember going deep into this subject in Muggle Studies…"

Alina nodded in agreement. "Not really," she replied.

"Percy, uncap your pen," ordered Annabeth as Percy obeyed immediately. Alina and I gasped in horror as the pen elongated into a three foot long, sword.

"Wh… Wha… What's happening?" I stuttered. What am I doing? I never stutter. Alina was now practically ripping my arm into pieces. Ooo! I felt a bone crack… I'll have to use Episkey.

I turned to Alina then whispered. "Cover for me… Or quickly use Episkey discreetly on my hand. I felt a bone crack…" Alina nodded and did it. My thumb went unbearably hot then cold as ice. It was then back to normal. "Thanks!" I whispered then sighed in relief. I didn't notice the younger boy waving his hand in front of my face right away then almost jumped off the couch in surprise.

"Where were we?" I asked innocently but my eyes were furious as my mouth turned into a scowl.

"We were just asking if you believed in the Greek Myths, but then you mumbled something about Muggle. Puggle…" Nico trailed off.

"Never mind we said that…" I said. "But why do you people carry weapons all the time?"

"The Myths. They're real. Percy is a son of Poseidon, Annabeth is a daughter of Athena, and I'm… a loner, son of Hades."

"Hmph," replied Alina. "Prove it!" I watched in awe as Percy controlled the water in the sink and how Nico summoned creatures from the Underworld and back. Annabeth kept ranting on about architecture and so on till my ears began to hurt. Alina then asked a very good question, one that was in my mind the whole time. "What do we do? How much time do we have? Is there some monster after us? We don't have our own weapons!"

"We go now," replied Percy. "Your mum knows. She knew all along. Isn't that why they always find their way to New York around their thirteenth year?" I listened to the way Percy strung the words together. It makes perfect sense…

"We're ready then…" I said confidently as I grasped my sister's hand. "Let's go."

Annabeth's POV
Percy led us out of the apartment till we got out onto the streets. I turned to Nico. "Are you up for shadow travel again?" Nico just nodded then instructed us to link hands. We were then pulled into the shadows. Through my jacket, I could feel the coldness but it really didn't affect me. I was having fun. It was just a little breezy. I turned and glanced at Allegra and Alina to see if they were okay. The chill didn't bother them at all. Oh how they were so similar to Nico. They truly must be siblings. The three of them reek of death!

From the darkness, colors began to come back and we began so slow down. We were past a large pine tree in which a bustling camp opened up behind. "We're here!" I exclaimed showing the camp to Alina and Allegra, who were pretty impressed. "Now let's get you to meet Chiron and Mr. D."

Allegra's POV
I followed Annabeth, Percy, and Nico till we got to the large building called the Big House. Walking inside we saw a man reading wine magazines and a centaur. I couldn't believe it! There was a centaur just like Firenze. "Oh my gosh!" I said as Chiron turned around. "You're just like Firenze, another centaur in Britain. Do you know him?"

"Yes child… But I think we have other matters to attend to. Annabeth, take them to the Hermes cabin and Nico, back to your cabin. Don't use your abilities so much…" Percy dragged Nico off to the Hades cabin as Annabeth led us to the Hermes cabin.

"This is cabin 11, the Hermes Cabin. All those who are unclaimed stay here… There is a claiming ceremony at campfire every night now. By the way, how old are you?"

"We're in our thirteenth year though we will be turning fourteen soon…" replied Alina. "I'm younger than Allegra by fifteen minutes…"

"Nice…" murmured Annabeth as she opened the door.

"Regular or undetermined?" asked a young girl named Dinnie.

"Undetermined, though we have several guesses on whom the parent might be," replied Annabeth as she left the cabin. Alina and I were led to a bare spot on the floor of the cabin. The cabin was dusty and a little filthy but it was better than nothing. Dinnie tossed us sleeping bags and we unrolled it claiming our small patch of floor. As the conch horn blew, everyone lined up, getting ready for dinner. Each cabin lined their campers by seniority then the cabins by the seniority of their parents. The Hermes cabin was the last of the ones in the Olympian council but there were far many cabins after with the children of the minor gods. This enabled Alina and I to observe the details in architecture carefully, and absorb our surroundings.

There was a brazier in the middle of the mess hall and a whole lot of tables. By the time, we received our platter of food and made a sacrifice, Alina and I rushed back to get a spot on the bench before it was full. Then, we would have to sit on the floor. Today's meal was macaroni and cheese, with a baked chicken leg. We could choose between a side platter of soup or salad. I picked the salad while Alina picked the soup. We would share.

The macaroni was al dente but the cheese was a bit too cheesy for my taste. For my solution, I mixed the shredded meat of my chicken and added some salad greens. To some, it looks gross, but at least it wasn't as cheesy as earlier. My happy pleasures of eating were disrupted by an announcement.

Chiron informed, "There will be no Capture of the Flag tonight but tomorrow, there will be double time. Instead we will have a longer Campfire and Claiming Ceremony tonight." Everyone groaned as the sound filled the Mess Hall. Capture the Flag was one of the highlights of camp where you can test your abilities in a full fledged friendly battle. I overheard Dinnie making plans with the rest of the Hermes cabin while Alina and I were quietly munching. Thirty minutes passed and dinner was over. It was the Hermes cabin's turn to help clean the Mess Hall so as everyone left, some of use were folding the tables, washing the dishes, and mopping the floor. Every once in a while, a tree nymph would come in bringing empty garbage bags in and full ones out. An hour later and about half way into Campfire, we were done.

"Alina," I said. "Let's find a spot in the front." She nodded in agreement. At Hogwarts, we were always in the front. No matter what, us Ravenclaws, always found a way to be in the front or as close to the front as possible.

The Apollo cabin was lined up with their guitars, drums, speakers, and microphones in the center of the Campfire where there was some elevated ground. They were really musical and pulled of the performances with aplomb! The Aphrodite Cabin was dancing, the Demeter Cabin was clapping and everyone was having fun. All of us were having fun until the Claiming began. First several girls were claimed by Aphrodite, and then a boy was claimed by Zeus. Several more boys were claimed; one by Hecate, two by Apollo, and one by Dionysus. Then it was our turn. As Alina and I walked up to the platform, a hologram began to spin on our heads. Nico stared in shock since when we looked up, it was in a shape of a helm; a Helm of Darkness. Everyone gasped, because finally Hades broke the oath. But he really didn't since, as part of Percy's wish, the oath was demolished when he wanted all gods, half-bloods, and the kind Titans to be recognized. Chiron said, "That concludes our Claiming for tonight. Please go back to your cabins. Remember double time for Capture the Flag tomorrow!"

Alina and I filed out of the Campfire and went into the Hades cabin. Remember earlier? We already shrank our trunks so everything is in our zippered jacket pockets so we already have everything. The cabin was gorgeous! The dark obsidian walls were gleaming and green and black fire was burning 24/7 in torches. Nico really did well when he was designing. There were three beds; two on one side, and one on the other. We even had a second floor which was designed into a game room and study area. The bathrooms were spacious too. As Alina and I picked a bed, we found an orange camp T-shirt, necklace with our name (the camp necklace… They will add beads later on), and a large thick envelope with barely legible handwriting. I opened the envelope to find a long note and some trinkets. Alina had some too. In the envelope, mine had a thick black leather bracelet with metal links down the middle. In the center, there was a beautiful obsidian watch face. If you tilt it into the darkness, the watch face disappears and looks just like a smoothed and polished obsidian stone. Also in the bag, I found a black marble with stygian ice core, a black/silver ring, and a black apple iTouch. Opening the note I began to read.

Dear Allegra,
Included in this envelope are several magical items. The watch/bracelet is a shield that will repel anything and everything. It works by engulfing you by a light gray shadow in which is translucent. Things cannot go inside, but your weapons can go out and battle another. To activate it, press the tiny black diamond jewel hidden on one of the steel links. To deactivate it, press the jewel again. Remember to charge it with darkness each night. If you charge it every night, it will work during the daytime and will not run out of charge. If you need to use it a night or visit me in the Underworld, it doesn't need to charge since it runs on Darkness. This is also when the power is the strongest. The marble is an enchanted marble that can enlarge into a dark vortex. With it, you can store any item no matter how big or small it is and it will always be with you. It can also enable you to control/conjure ice and black fire. The ring with a tiny engraved skull is your main weapon. It's name is Onyx. It is a shifter therefore can turn into any weapon that you need. It was crafted from the finest Stygian Iron with the help of Ares and Hephaestus. The hand grips are made of stygian ice wrapped with dragon and drakon skin. Finally your black apple iTouch… This iTouch is from Athena and Artemis and is an mp3 player that can connect to both the mortal and immortal music stations/videos/etc. If needed, it will morph into a laptop. This is also your back-up weapon. When you press the Battle Tower symbol, two knives with form…. The one on your left hand will have a silver blade that is coated with stygian iron while the knife in your right hand is a silver blade but coated in celestial bronze. The iTouch's name is Pluto. One last thing, all your magical items will return when lost, but when they return they will be reverted back into their disguised form. Good luck and use these well.
Hades

I turned and looked at my sister. Her eyes were bugging out! From dad, she got two black earrings which turned into stygian iron daggers, a bracelet that springs out into a shield, a cell phone that morphs into a bag that holds anything, and three skull rings made of bone. Alina called Nico over to us then gave each of us a ring. "Dad said to give you these. The ring is kind of like an empathy link but if one of us is in trouble, or something and needs help, the ring with automatically teleport the three of us to our cabin here, to the Underworld, or just group the three of us together and randomly appear somewhere. Whichever one is closer. Also, if you need to see Dad, just twist the skull on the ring."

Nico and I just nodded along while Alina then opened the cell phone. She took out her trunk then cell phone absorbed it. The cell phone then returned to her pocket. As I went back to my bed, I put my trunk inside the marble then changed into pajamas. I then hopped into bed. Nico and Alina followed suit then we said, "G'night!" The 24/7 hour flaming torches dimmed their light and we all fell asleep.

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Wings (me): Okay… How was the first chapter? I think I did pretty good… The ending was a little hard to write but I guess it paid off! I feel like I'm going to need a few more charries but I don't want to make them up. I might end up asking my sister... or best friend...

Allegra di Cipriano (Pronounced: ahl-LE-grah; the Italian way)
Alina di Cipriano
(Pronounced: ah-LEE-nah)

Allegra and Alina di Cipriano are identical twins except for the fact Allegra is an inch taller, has darker skin, and is fifteen minutes older than Alina. Other than that, they both have super straight, sleek black hair; coal brown/black eyes, and a slender/athletic figure. Allegra's hair is layered and reaches to the bottom of her ribcage. She also has framing bangs that fall on the left side of her face emphasizing her angular features. Alina's hair is also layered but she has framing bangs to the right side of her face but her hair is cut shorter than Allegra's. Alina's barely touches her shoulders. Both are very musical and can play instruments; Allegra plays the cello, piano, and drums while Alina plays the viola, guitar, and flute.

As you know, Allegra and Alina are both 13 years old almost fourteen. In this story, Nico is around 14 years old too while Percy and Annabeth should be around 17-19 years old.