Hey readers! This is my attempt at a Percy Jackson and Harry Potter crossover. I am trying to keep everyone in character as far as possible without damaging the plot, so do tell me if I have gone wrong unintentionally.

Guys, Chapter 5 of "The Seventh Child – Prophecy of the Seven" should be up soon – oh damn. I should not have said that. I should not have told you that. Oh well…

Disclaimer: I do not own Percy Jackson and the Olympians, Heroes of Olympus, Harry Potter and all associated characters.

Prologue

Camp Half Blood

If one possessed the ability to fly, without wings or machine, and then hovered over Long Island, one may be blessed enough to see some sort of resort. A strange resort, but a happy place, no doubt. And this would not be far from the truth. For only a week before, on the eighteenth of August, a Great War had taken place. Had one possessed the ability to see what was happening at Manhattan, they would have noticed forty teenagers, no older than sixteen years of age, fighting swarms of monsters. But the greatest battle was not in the streets. Quite to the contrary, the battle of battles had taken place in the skies, six hundred stories above Earth. Mount Olympus. The home of the Greek Gods and Goddesses. They truly were immortal, even going so far as to populate the world with their children - demigods, they called themselves. They were powerful beings, each owning a weapon capable of mass destruction. Oh, it was not always a physical manifestation, for sometimes, as eleven-year-old Annabeth Chase, daughter of Athena rightly said, "Sometimes even strength has to bow to wisdom." Nonetheless, they were powerful beings, capable of controlling the forces of nature in contravention to the laws of science that mortals had propagated. They defended the world from evil, the most recent of which was the dangerous monster Typhon and the Titan Kronos.

The week before, in the Throne Room of Mount Olympus, the Titan Lord had been defeated by Perseus 'Percy' Jackson and Annabeth Chase, with help from their satyr friend, Grover Underwood. Percy had been offered godhood as a reward for his services to Olympus, but he turned it down in favour of helping the undetermined demigods get recognised and respected, as everyone deserved. Annabeth had become the Architect of Olympus, and Grover a Lord of the Wild.

At Camp Half Blood, two people walked slowly on the beach, savouring their time alone together. The hero and heroine of Olympus, Percy and Annabeth were enjoying their time together. They had been best friends for almost five whole years before, on the day the Titan War ended, he finally asked her out. They had been through a lot, and were basking in the peace, hoping that it would last. They had no idea how wrong they would be.

A conch horn sounded in the distance. Percy smiled at the thought of food, especially his favourite drink, blue cherry coke, and suddenly bent down, picked Annabeth up, threw her over his shoulder and raced to the dining pavilion. She shrieked, and pounded his back even though she knew he wouldn't get hurt. Percy laughed at her efforts and set her down at the Athena table, which he never dared approach with a pole for fear that Athena herself would smite him for dating her daughter. He knew she was one of the worst enemies to make, simply because while Ares or Dionysus would attack him or curse him, Athena would find a way to get back at him, Hero of Olympus or not. And he liked to stay with his parts intact, thank you very much.

Annabeth laughed, "Seaweed Brain, my mom won't do anything to you, why don't you drop me off at my seat?" She said. He could hear the smile in her words. He smirked, and dropped her on the floor. She yelped in mock pain, and glared up at him. She got up, dusted herself off and put her hands on her hips, still glaring at him. He cringed and she smirked a little. "Perseus Jackson. Why did you drop me?" She said with gritted teeth, daring him to say something he would regret. He slowly backed away from her, trying to reach his table, but she wouldn't let him. Ah. He then remembered the issues with dating a daughter of Athena. Too damn smart.

Percy was saved from an extremely embarrassing situation by Chiron stamping his hoof on the pavilion floor, at his position by the head table. He made his usual announcements about how sacrifices, and introduced two new campers, a Daughter of Hecate and a Son of Hermes. They were both directed to the Hermes cabin, since the Hecate cabin hadn't been built yet. Connor Stoll welcomed them, and Percy shuddered, pitying the new kids' plights. The Stoll brothers, contrary to popular belief, were not twins, but a year apart in age. They were the Camp's pranksters, their most favourite target being Katie Gardener from the Demeter cabin. Of course, everyone knew that Travis only pranked Katie to get her attention; he really liked her. Percy snickered to himself, and smiled at Annabeth when she came up to his table.

"Hey seaweed brain, have you forgotten that we have swordsmanship now? And that you are supposed to be teaching?" She said, the slightest hint of humour lining her voice. Percy said something real intelligent like, "Uh... Huh?" He snapped out of his reverie, and ran off to his cabin, just to realise that the arena was in the opposite direction. "Styx!" He cursed, ignoring the thunder that rumbled above his head.

He reached his swordsmanship class slightly out of breath, but that didn't prevent him from putting everyone, especially the newbies, through their paces. He was a good teacher, patient and kind, yet firm, and emanated an aura of calmness, like the sea on a cloudless day. He had no idea that his day would get a lot more complicated.

After swordsmanship, Annabeth was called to help a new Athena camper. Percy went to the beach to practise his powers over water, for he was the Son of Poseidon. He began by trying to summon water from within himself, as he had learned when he inadvertently blew up Mt. Saint Helen's. He managed to form a small ball of water, about the size of a tennis ball, marveling at the clearness and purity, something which the waters of the East River and Hudson distinctly lacked. The importance of the sand dollar struck him then, for it had cleansed the river of pollution, something anyone with a connection to water no doubt craved. He then worked on evaporating it, freezing it. Suddenly he had an idea. He stood knee deep in the water of Long Island Sound and threw the ball of ice as far as he could. As soon as it left his hand, he focused on it and tried controlling its motion. At first, he wasn't able to, but in the end, his efforts were rewarded by the ball zooming back to his hand. Satisfied that he had learned a new power, he looked at his watch. He had an hour and a half before he went to meet Annabeth. He dove into the water, talking to the creatures, until a school of hippocampi raced up to him.

"My Lord, we need your help! A nymph is being tortured near here, lord!" they neighed in Percy's mind.

Anger filled Percy's mind as he thought of an innocent person being helplessly punished. He shot off through the sea, forcing the currents to propel his journey, and arrived there quickly. He was greeted by a scene he wouldn't forget in a hurry. Triton was attacking a nymph with lust in his eyes, and the poor nymph was unable to defend herself from his onslaught. Percy uncapped Anaklusmos, and swam in front of Triton, separating him from the nymph. Triton's eyes quickly changed emotion, from lustful to furious. The hippocampi took the battered nymph away carefully, while others spread the word about the imminent fight between the Princes of the Sea.

Triton faced Percy, both of them rising through the ocean while circling each other. They were in the centre of the ocean, one wielding a trident, the other a sword, both glowing with an aura of power, being children of the sea in their domain. Without warning, Triton rushed Percy, aiming to run him through with his trident. But Percy wasn't known as the best swordsman in 300 years at Camp Half-Blood for no reason. He glided to the side, using the water to support his movements, simultaneously manoeuvring his sword to block the trident jab. The resounding clang of divine metals crashing against each other could be heard miles away in the ocean. Percy summoned the currents between him and Triton, realising that Triton had interpreted his interference as a challenge, and that he was now at the mercy of the water god. Sure, he had faced off against Titans, but he had had help. This would be a different battle. The sea would constantly have to choose between its Princes, and that meant that he couldn't rely on his powers over water much. He would have to hold Triton off for as long as possible. Hopefully, his father would come and put an end to this madness. With a jolt, he realised that even his father was helpless. Stopping this would create a rift in his already fragile family, one that may not be reparable. He would have to beat Triton or be beaten by the enraged grandson of Oceanus.

Percy was brought back to his situation when he felt the currents change. He looked up and saw Triton charging at him, eyes smouldering with anger. He braced himself for a hard fight, and wasn't disappointed. They exchanged blows rapidly, neither backing down, both bolstered by the presence of water all around them. Percy then crossed blades with Triton, forcing him to pause. He put pressure on the currents above him, and had them push him down, surprising Triton. He quickly shot towards Triton from behind, shocking him, and ran his sword through his side.

Triton's eyes bulged. The fury in them was palpable. He ripped Riptide out of his body, and burst into his divine form, sending out a blast of energy, causing Percy to black out from the surge of energy that passed through his body. His unconscious form was thrown back into the depths of the oceans.

Percy groaned. He had washed up on the shore of some sort of lake, and his body was aching. He looked around, trying to rub the stars from his eyes. His head pounded, possibly the after effect of Tritons energy blast. Suddenly, a hellhound attacked him from the shadows. Percy was thrown back into a tree, caught off guard by the sudden attack. He stood up shakily, taking Riptide out of his pocket and uncapping it slowly. He braced himself for the inevitable attack, and wasn't disappointed by the vicious lunge the hellhound took at him. What he was not expecting, however, was being shadow travelled along with the hellhound. He tried smashing it with riptide, but it was knocked out of his hand, and it would be a few minutes before it returned to him. The hellhound clawed at him, ripping his orange camp t shirt apart. Suddenly Percy felt the familiar cold that he had come to associate with shadow travel. All he knew was darkness.

"It is also my painful duty to inform you that the Inter-House Quidditch Cup will not take place this year."

"What?" Harry gasped. He looked around at Fred and George, his fellow members of the Quidditch team. They were mouthing soundlessly at Dumbledore, apparently too appalled to speak. Dumbhedore went on, "This is due to an event that will be starting in October, and continuing throughout the school year, taking up much of the teachers' time and energy - but I am sure you will all enjoy it immensely. I have great pleasure in announcing that this year at Hogwarts -"

But at that moment, there was a deafening rumble of thunder and the doors of the Great Hall banged open.

A man stood in the doorway, leaning upon a long staff, shrouded in a black traveling cloak. Every head in the Great Hall swiveled toward the stranger, suddenly brightly illuminated by a fork of lightning that flashed across the ceiling. He lowered his hood, shook out a long mane of grizzled, dark gray hair, then began to walk up toward the teachers' table.

A dull clunk echoed through the Hall on his every other step. He reached the end of the top table, turned right, and limped heavily toward Dumbledore. Another flash of lightning crossed the ceiling. Hermione gasped.

The lightning had thrown the man's face into sharp relief, and it was a face unlike any Harry had ever seen. It looked as though it had been carved out of weathered wood by someone who had only the vaguest idea of what human faces are supposed to look like, and was none too skilled with a chisel. Every inch of skin seemed to be scarred. The mouth looked like a diagonal gash, and a large chunk of the nose was missing. But it was the man's eyes that made him frightening.

One of them was small, dark, and beady. The other was large, round as a coin, and a vivid, electric blue. The blue eye was moving ceaselessly, without blinking, and was rolling up, down, and from side to side, quite independently of the normal eye - and then it rolled right over, pointing into the back of the man's head, so that all they could see was whiteness.

The stranger reached Dumbledore. He stretched out a hand that was as badly scarred as his face, and Dumbledore shook it, muttering words Harry couldn't hear. He seemed to be making some inquiry of the stranger, who shook his head unsmilingly and replied in an undertone. Dumbledore nodded and gestured the man to the empty seat on his right-hand side.

The stranger sat down, shook his mane of dark gray hair out of his face, pulled a plate of sausages toward him, raised it to what was left of his nose, and sniffed it. He then took a small knife out of his pocket, speared a sausage on the end of it, and began to eat. His normal eye was fixed upon the sausages, but the blue eye was still darting restlessly around in its socket, taking in the Hall and the students.

"May I introduce our new Defense Against the Dark Arts teacher?" said Dumbledore brightly into the silence. "Professor Moody."

Customarily, new appointments to staff were greeted with a round of applause. Evidently, the entire school forgot about this custom, with the exception of Dumbledore and Hagrid. They clapped briefly for Professor Moody, but it sounded hollow against the silence of the Great Hall.

Sensing the tension in the Great Hall, Dumbledore continued his speech, "As I was saying, I have great pleasure in announcing the Hogwarts will be -"

CRASH!

For the second time that night, Dumbledore was interrupted by the arrival of a stranger. A boy, no older than sixteen, with tousled jet-black hair and brilliant sea green eyes, crashed into the Slytherin table, right in front of Malfoy. Suddenly, all the shadows in the room seemed to gravitate towards one spot, and from that spot burst a huge dog. The dog pounced on the boy and a high-pitched squeal could be heard from Malfoy. The boy scrambled backwards on the table picked up some sort of knife and tried slashing at the beast. It promptly burst into a fine golden dust that drifted away into the air. The boy collapsed onto the table, unconscious.

There was a moment of absolute silence in the Great Hall. Then everyone began to panic. There were screams all around the room, and everyone began to stampede their way out of the Great Hall.

"SILENCE!"

That one word solicited a complete halt of movement in the Hall. Every single student, ghost and teacher froze in whatever they were doing. Even Crabbe and Goyle stopped stuffing their faces with cake to listen to Dumbledore. He went on, in a much calmer voice, "Will all prefects please escort their houses to their respective dormitories. Will all teachers please accompany me to the hospital wing? Madame Pomphrey, if you will -" he concluded, waving a hand in the general direction of the boy.

The teachers all rose as one, and Madame Pomphrey waved her wand at the boy who had put a crack in the Slytherin table. She transfigured his clothes into hospital robes, and levitated him all the way to the hospital wing. Once there, she laid him down on one of the beds, and went into her office. The teachers all surrounded the bed, taking up various positions around the boy - some sitting, some standing, until Madame Pomphrey bustled through to the bed. She fed him some Wideye or Awakening Potion and turned to Dumbledore. "He should wake up within the hour, Headmaster," she said. The rest of the teachers sighed and went back to their duties on the first day of term - checking their Houses were in order and preparing for their classes, which would begin the next day.

After the teachers left, however, the boy began to jerk violently in his bed. Sparks flew out of his body, and Madame Pomphrey whirled around in alarm. She took out her wand, and tried to place a restraining charm on him, but nothing happened. She turned to Dumbledore, who immediately understood what she wanted him to do. He took out his wand and gracefully cast a spell to subdue the teen's irrational response to the potion - for what else could it be? However, like Madame Pomphrey, his spell had no effect on the boy. On the contrary, it only seemed to accelerate his "fit". Dumbledore was shocked. Never had he read of such an event - where some young witch or wizard reacted adversely to the use of healing and offensive magic. Of course, Madame Pomphrey had levitated him earlier, but she had not done anything to the boy, hence the lack of a reaction then.

Suddenly, the fit subsided, and the boy's eyes shot open. Dumbledore looked at his eyes and was shocked by the infinite power they seemed to hold. They were like the sea on a stormy day, conflicting with itself and the tips of the waves bearing no colour. These weren't the eyes of an innocent schoolboy. These were the eyes of those people who had experienced loss. These were the eyes Dumbledore saw in the existing members of the original Order of the Phoenix. These were the eyes he saw when he looked into the mirror when he thought about Ariana. These were eyes that had seen death and destruction, pain and misery, and above all, loss.

"Wh-where am I?" said the boy, his hand drifting to a nonexistent pocket. "Who are you? Where are my clothes!" he added, becoming slightly hysterical. True, he was no longer shooting out sparks, but that did not encourage Dumbledore to approach the boy. Keeping his distance, the Headmaster replied, "You, my boy, are at Hogwarts School of Witchcraft and Wizardry. I am Albus Dumbledore, Headmaster of this school, and a wizard. I suspect, by the fact that you were able to enter our grounds and halls, that you are indeed one too. But first, what is your name?"

"Perseus - although I go by Percy - Jackson, sir." Percy replied hesitantly. He was confused. Wizards? This man spoke with a clear British accent, indicating that he was somewhere in Britain, but he remembered fighting Triton off the coast of New York. He supposed that if the Gods could exist, then so could the wizards. He asked the old man - he had to be old, what will all that silvery hair, "Sir, what is the date?"

Albus Dumbledore was intrigued. This boy had a distinct American accent. He seemed to accept that he was a wizard quite calmly, although he obviously had not heard of the place beforehand. He replied, "It is 1st September, Mr. Jackson. Might I ask where you are from?"

"New York." said Percy immediately. He realised he was far away from home, and had been out for almost a week after his fight with Triton. It was probably some cruel trick of the Fates. Would he never have peace in his life?

"Do you know of Harry Potter?" asked Dumbledore. He knew that this was the surest test of wizardry - there was no soul who was a part of the wizarding world who did not know who Harry Potter was.

"Harry Potter? I don't, Headmaster. Should I?" he replied, that confused look still on his face.

Dumbledore sat back on the chair he had conjured up for himself a while ago, stroking his beard, deep in thought. This boy - Percy - evidently did not know of the wizarding world at all. So he decided to tell him. After all, if his deductions were right, this boy had seen war, and could possibly be a good friend to Harry if ever Voldemort rose again - something that was evident, especially considering Harry's rather vivid dream over the summer.

"Harry Potter is somewhat a legend in our world, Mr. Jackson. He is the subject of a terrible prophecy that, thirteen years ago, led to the slaughter of his parents by a Dark and evil wizard named Lord Voldemort." Percy let out a snort at this, but remained silent, intrigued by the story of this boy. Dumbledore was amused at the reaction to the name, but knew that this boy was exceptionally brave, or simply did not know the damage Tom Riddle had wrought upon the world. Choosing to go with the latter, he went on, "But Voldemort could not kill little Harry. The curse that he had used to kill him, rebounded upon him, and he vanished that night. Ever since then, Harry Potter has been known as the Boy-Who-Lived, with a characteristic scar on his forehead that seems to share a unique connection with Voldemort. This connection has led us to believe that Lord Voldemort is attempting to rise again, just as he tried twice these past three years."

Percy was silent for a while, and thought heavily on the course of action he should follow. He had a strange feeling that he should not be there, but at the same time that he belonged there. He realised that these wizards knew nothing of the gods, and decided to keep it that way. He also knew that if there was a war coming, maybe he could help. After all, he was the son of one of the Big Three, and he wanted to help avoid the loss of life as far as possible.

"Sir, do you really believe that a war is coming?" asked Percy carefully. The answer to this would determine whether he would stay or leave this place.

"I do, Perseus," said Dumbledore, taking in the boy's flinch at the name, "It certainly feels like it, and I know that sooner or later, Voldemort will rise and threaten this world again, just as he did until thirteen years ago. I fear for the lives of our people when he rises once more."

Percy listened carefully, and knew that his heart had made his decision for him. He could not stand back and let these people fight a war in which he knew, deep down, that he could help change. He said, "Sir, I have seen war. I would like to help you when the time comes, and assist you in the war that you believe is coming. With your permission, sir, may I do so?"

Dumbledore was astounded. He knew that there were precious few who would willingly involve themselves in a war which they could walk away from. He admired the selflessness of the boy, and with these thoughts in his mind, he said, "Very well, then Mr. Jackson. I would like to offer you a place in this school. Tell me, will you attend Hogwarts School of Witchcraft and Wizardry?"

"Yes sir, on one condition," said Percy, after mulling the offer about in his head, "I wish to contact my mother and girlfriend, and let them know where I am, so that they do not panic. A warning though, sir. I have a tendency to get kicked out of every school I attend, through no fault of my own. I will try not to blow up your school, sir, but I give no guarantees."

Dumbledore chuckled. "Do not worry, my boy, we shall work something out. Now, rest, I will have someone bring up food for you tomorrow. We will sort you into your House at dinner, and visit Diagon Alley for all your school materials the day after."

"Um sir? Houses? And sir," said Percy sheepishly, slightly embarrassed, "I haven't any money."

"Houses will be your home, your family, for however long you study at Hogwarts. The four houses are called Gryffindor, Hufflepuff, Ravenclaw, and Slytherin. Each house has its own noble history and each has produced outstanding witches and wizards. While you are at Hogwarts, your triumphs will earn your house points, while any rulebreaking will lose house points. At the end of the year, we award the House Cup to the House with the most points. Let us see how this year turns out, hmm, Percy?" said Dumbledore, his blue eyes twinkling mischievously, "As for money, Hogwarts has an allowance for those who need it, and we will pay for your education here, Mr. Jackson. But all that later! For now, sleep."

Percy lay down after Dumbledore left, and drifted off into sleep. He hoped he would not have any demigod dreams, but he wasn't in luck. His last thought was that this would be a very interesting year.

Percy then found himself in a palace. He knew it wasn't on Olympus, after all he had been there a few times while Annabeth was reconstructing it. He looked around, and saw three identical old ladies who he had seen only twice before in his life. The Fates. As his eyes fell on them, they spoke in unison, like one voice tripled.

"Perseus Jackson."

Cliffhanger on the Prologue, not very nice of me. Now, I do not have any strict updating schedule, so I will try to do Chapter 1 as soon as I can, but I have my studies and SAT to focus on, so no guarantees.

Tell me what you think!

Curtain fall, Blacklist1000