Author's note: This is my first HP and PJO crossover so I hope that it'll go well. It's been YEARS since I read the books (I only read up to book 3 for both series and watch all the movies for HP) but it doesn't really matter if you haven't as well since the books will be mentioned very little here.

Disclaimer: I own nothing you recognized from the books.

Warning: May be OOC, grammar/spelling, character deaths, etc. This has nothing, I repeat, NOTHING to do with the HP fanfiction My Immortal nor with Beethoven's My Immortal Beloved.

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The first time Harry saw him, he was five and was at his favourite beach.

Harry was playing around the beach for sometime before his godfather suggested for him to go swimming. Excited, he ran straight into the water without waiting for Sirius to come with him. The boy swam near the bottom of the not-so-shallow water so as to not worry the adult. He was so intrigued by the colourful fishes, pretty corals and unique sea molluscs that it took him awhile to notice the presence.

It turned out to be a male in his late teen years or a young adult. Just like Harry, he had messy black hair. The male was wearing a simple button-up shirt and black jeans but seemed to be able to move perfectly in the water. As if, just like the boy, he was able to breathe in all bodies of water. But the thing that captured his attention the most was his eyes. They were green, just like Harry's. However, instead of emerald green, they were sea green and blended nearly perfectly with the water surrounding them.

The stranger gave him a melancholy smile and wordlessly extended his hand out in invitation. He accepted and they began to dance to a silent tune only the both of them could feel and understand. Not once did the young boy think that it was weird, that things like this transcend any normal human nature. For him, the only thing that matters was the man in front of him. They danced for what seemed like hours before both were brought back into reality.

"Harry! Where are you, kiddo? Come on, it's time for your nap. Lily will kill me if you skip it."

Harry turned his head around to look at the mystery man but said man had already vanished.

...ooOoo...

The second time they meet, Harry was eight and was at the meadow near his house.

His parents, godfather and uncle Moony were busy at the moment to prepare for the party so Harry, after asking for permission, went to the meadow to play by himself. Theirs was a quiet and peaceful neighbourhood so his parents were not worried that anything untoward will happen to him. Once he arrived, he began to pretend that he was a courageous knight off on a quest to rescue trapped princesses and fight fearsome creatures. He was so into it that he did not notice the chuckles until the wind carried it into his ear. Turning around, he saw the sea stranger again. Harry smiled widely and it was his turn to extend an arm in an invitation. The man accepted with a smile and this time, they were wizards trying to stop an evil man trying to conquer the world. They played for hours on end until Harry noticed the setting sun and the sky was red with streaks of pink, orange and soft violet.

The young boy turned to his companion with a sad smile on his face and immediately the male knelt down in front of him so that they were looking at each other eye to eye. The stranger with sea green eyes that kept haunting Harry's dream cupped his face gently and tenderly rubbed comforting circles with his thumb as if to reassure him that this would not be the last time they meet. Harry leaned into the warm hand and closed his eyes, wishing that the moment would never end. Sadly, this time they were interrupted by a shout too.

"Harry, it's already sunset. Come inside and take a shower."

Looking at the mystery man, Harry saw him taking a small wrapped package from his pocket and gave it to the birthday boy. The boy with emerald green eyes smiled happily and wrapped his arms around the man's neck in gratitude; Harry absently noted that he smelled like the sea. The older male chuckled and the younger male was mesmerized; his voice was like velvety soft rose petals and it cocooned Harry in a warm embrace. The stranger smiled again and tenderly kissed his forehead before gesturing for him to return home.

He obeyed and once he reached his house, he turned around and again, the man had vanished.

(When he was at the safety of his room, he opened the gift and saw a black choker. Its pendant was a round emerald surrounded by tiny sea green gemstones.

He never took it off.)

...ooOoo...

The third time they meet, Harry was twelve and was doing his summer homework at the library.

He was trying to write an essay for Creative Writing class and he just could not think of anything. He was usually very imaginative because he had dreams that were so amazing and surreal yet feel so tangible and concrete at the same time but it seemed that his imagination was taking a vacation. That, or his brain was fried from the heat. He suppressed the urge to bash his head on the desk, only to end up using crossing his arms and use them as a pillow, muffling his exasperated groan. Imagine his surprise when someone took a seat beside him and he looked up only to see his stranger. Yes, people. The stranger was officially his in Harry's mind. The older male casually took out an iPod, stuffed one of the earbuds in one ear and offered Harry the other. The teen with emerald eyes grinned and after that, the rest of the hours together were filled with music, pen scratching on papers and the sound of book pages being turned.

When all of his homework was finished, Harry hesitated. He knew what was coming next but he did not want them to part again. Call him obsessed but meeting him two times in the past were enough to make him crave for this man so he just sat there, not knowing what to do. Fortunately for him, he did not have to make the decision.

The familiar stranger (and that was irony at its finest) gently put his book down and twisted in his seat to face the tense teen. Harry could feel those intense eyes tracing his facial features. His forehead, his eyes, his shapely nose, his cheeks, his jaws, his chin before finally arriving at his full lips and lingering there for a moment before moving downwards. An amused smile graced the man with sea green eyes' lips when he saw the choker given to the teen. Harry tensed even more when one finger gently and oh-so-sensually traced the choker reverently and lovingly. Up, down, left, right, a circle here and there, repeat.

"You know," Harry whispered quietly, gaining the man's attention, "you never did tell me your name. It's a bit unfair."

"Unfair? How?" A slightly boyish but sultry voice with a rough lilt replied, tinged with amusement.

"You keep haunting my dreams yet I don't even have the slightest clue as to who you are. And," here, he pierced the stranger with a look, "I'm willing to bet that you know every single thing about me."

"Let's do this properly then." The man smiled and held out his hand. "My name is Perseus Jackson but you can call me Percy. Nice to meet you."

"My name is Harry Potter." Harry replied easily and shook Percy's hand. "Nice to meet you too, Percy."

They did not let go immediately, savouring the feel of each other's hand. Percy's hand was rough and showed signs of someone who did not mind hard work while Percy marvelled at the softness of Harry's palm yet the slightly rough texture proved that the teen was not a spoiled brat. They sat in silence for a few minutes before Harry broke it.

"Your mother must really love you."

Percy looked at him with expectant eyes, as if he was waiting for something. "Why did you say that?"

"Because Perseus was the only hero that had a happy ending in Greek mythology."

The eyes softened and Percy whispered, "Yeah, you're right. She did."

Harry caught on quickly. "Oh, I'm sorry! I didn't mean to -"

"It's fine." Percy cut him off, stopping his string of apologies by tenderly rubbing circles on his cheek with his thumb. "I came into terms with her death long ago."

Another bout of silence reign before Percy whispered in an almost broken voice, eyes misty and faraway as if he had forgotten that Harry was there. "You've always been like this, Harry. You always notice the little things and that made me love you even more. They told me to forget about you but I can't…I just can't."

Harry was confused. "What are you talking about, Percy?"

Percy snapped back into reality but he did not reply Harry's question. They spent the rest of the day in companionable silence before Harry had to go home.

Harry went home with more questions than answers.

...ooOoo...

The fourth time they meet, Harry was fifteen and was reading a book under a tree at the beach where he first met Percy.

He was expecting Percy to just pop out of nowhere the way he had always done for the past decade and this time, he was not about to let the man walk away before Harry had his answers. True enough, half an hour into the book, Percy joined him in the shade with a grin.

"Hey, Harry."

Harry closed his book with a snap and pierced Percy with a look that clearly said 'I want answers and I want them now.' Percy raised his hands in a gesture of placation but Harry ignored it.

"What did you mean by what you said back then?"

Percy scratched his cheek, unsure how to answer. Oh, he could easily give the teen the answers he wanted but the problem was making Harry believe him. His heart would be torn to shreds if the teen rejected him. The teen saw his hesitation and decided to give him the push the man needed.

"You know," Harry baited, "My best friend has a younger sister. Her name is Ginevra but we just call her Ginny. Before summer started, she told me that she has romantic feelings for me and," Percy's eyes widened, "I'm thinking of accepting it."

What happened next was so fast that Harry completely missed it. One second he was leaning against the tree and the next he was already laying on his back, his arms were pinned above his head in a strong grip and Percy was straddling him, his face shadowed by his bangs.

"P-Percy?"

"You can't." Percy mumbled. "You can't be with her. You're mine. You promised me that you are mine. For eternity."

"Then answer me!" Harry yelled. "I know that you're not human. Ten years and you still look the same. Why me? Do you have any idea how frustrating it is to look forward to your next visit every time I went out? To not know even your name for the first few years?" His voice lowered to a whisper. "To love you despite not knowing anything about you."

Percy's grip faltered and they stared at each other, Harry's eyes moist with tears that Percy gently rubbed away.

"I…This is not the first life we met. As you have guessed, I'm an immortal and I've always been in each and every one of your reincarnation, trying to make you fall for me again."

"Why not just make me an immortal?"

Percy laughed bitterly. "I do. I've always wanted to but there's always something preventing me. Always."

"Will you do it in this life?" Harry searched Percy's eyes and what he saw filled him with elation.

"I will. So help me, I will. Nothing will stop me this time. I'll do anything." He buried his face in Harry's neck. "Anything."

Harry removed his hands from Percy's grip and gently cupped the latter's cheeks, making Percy raised his head.

"Then I'll wait for it. I love you, Percy."

"I love you too, Harry. We're staying together this time. You're not getting away from me. Never again."

Their lips met in a gentle kiss that was so full of emotion that Harry could not help but to cry again.