Authors note:

Thank you for giving this story a shot! I know PJO/HP crossovers have been overdone, but I'm definitely putting my own spin on this. I am currently editing this story, so I can tell you from the future that this is going to have some crazy stuff I haven't seen anywhere else in fanfictions yet. I hope you enjoy it. Any feedback, regardless how critical, is welcome. I am trying to get better so criticism does really help.

A huge thanks to 2017tnt, who is beta reading this story with a focus on language and Milton'sKnife who is helping me with the large scale plot. Without you guys this story wouldn't exist!

Time period: This starts off around a month after the last Heroes of Olympus novel. Trials of Apollo are not considered canon for the sake of this story.

Ships include: Percabeth, Caleo, Nico&OC, Jasper/Jiper, Frazel, Romione, Hinny

WARNING: If you don't like boy&boy romance, grand scale (lots of characters and plot points) stories, main character deaths, teenage banter and mysteries, then this ain't your type. (see what i did there? XD - lol sorry for the Nico reference).

Basically, this stories has both super light (funny&fluffy) and really dark sides, so if you don't like such a mix don't read.

Disclaimer: Even in my wildest dreams I do not own Harry Potter or Percy Jackson. sighs sadly

Prologue:

Night had fallen. Clouds covered the stars and the moon had not risen. Ronan couldn't see a thing. Yet he still moved at top speed; instinct and smell allowing his hooves to stay on the path.

The wind was ripping at his shirt, forcefully entering and chilling the satyr to the bones. Grover would want to hear of this, and the rest of Camp as well. His breath came in short bursts by now. Adrenaline was all that kept him pushing. Adrenaline… and fear. He had to make it in time. Before they arrived. He sped up yet again. He had seen how fast they were, he knew they had smelt him. And most importantly: every now and then, he heard the rustling of leaves behind him. Ronan didn't dare to look back. Although he'd never met a creature that could outrun him, something felt different here.

Camp Half-Blood was only a mile away; he was sure he had a fighting chance to reach it before they reached him. He could already see the arena and the big central farmhouse. The large bonfire over which the campers roasted marshmallows was still burning. Ronan could see some campers walking past the light. He opened his mouth to scream, to call for help, anything, but everything went quiet.

The rustling behind him had disappeared.

He couldn't hear his own panting or his voice as he tried to call for help. Suddenly, he felt cold. No, cold was the wrong word for it. It was a numbing freeze, as if winter had arrived unexpectedly and turned New York into an icy wasteland. The clouds had ripped apart; the moon was up. Ronan blinked, surprised. It wasn't supposed to be up yet- it was way too early. The moon was strong too, much stronger than Ronan had ever seen. The entire forest had been turned blue.

The satyr had stopped running; he knew it was too late. Shadows came out of the forest, approaching from all sides.

Ronan closed his eyes. If he had to die, he decided he wanted to die with honor. He had no weapons, having dropped his club to run faster. He had nowhere to go; the shadows had surrounded him. Ronan opened his eyes, his life having flashed before them. He didn't flinch when he could see their rotting, slimy faces under their black masks. He didn't flinch as they pulled their daggers. He didn't flinch as the blades were pushed into his body. Within the eyes of the shadow before him, Ronan made out a hint of recognition for his courage. That was the last he saw, for then he fell, dead.

His corpse vanished. Where he lay, a rose grew out of the forest floor. The shadows didn't see it; they were gone by the time Ronan's body had hit the ground.

Chapter 1:

"You can't be serious!" Percy exclaimed, pointing his finger at Chiron in disbelief.

"We've been through Tartarus, quite literally, and you're proposing another quest not even a month later?!"

Annabeth calmingly put her arm around her boyfriend. "I'm sure there is some sort of reason, let's just hear Chiron out." Percy usually didn't react like that. The war had left its scars on all of them. Some took longer to heal than others, the daughter of Athena knew that.

Chiron quickly took advantage of the silence that followed. "Yes, there is a reason. My brothers have informed me of them making contact with another tribe of centaurs, a tribe which is speaking of magic-using mortals."

"Wait, so you're saying wizards are real?" Leo asked, almost jumping up and down with excitement.

"That still doesn't explain why the hell we have to go on another quest." Percy glared at the centaur. From the five in the room, he was clearly the least impressed by the existence of magic.

"Let me explain. Fundamentally, there's no problem with the existence of such a group of mortals. The real problem is that numerous satyrs have been found dead or have disappeared recently, and from the lack of any physical wounds we are assuming that magic is at play. But not only that, multiple demigods have gone missing as well, and the oracle has not issued prophecies since the battle with Gaia. The mysteries are mounting."

Silence filled the room, even Percy was quiet for once. When nobody spoke, he said after a while, a thick layer of disbelief in his voice; "How can satyrs be disappearing? Grover spoke of nothing of the sort."

"Grover was instructed to keep the information a secret." Chiron replied, almost as if having expected that question.

It seemed like Chiron had convinced Percy to some extent, for the son of Poseidon didn't continue the argument.

"So what do you want us to do?" It was the first time Nico spoke during the meeting, his voice as cold as the stygian iron of his sword.

"We want you to infiltrate one of the wizards' main learning facilities. It is called Hogwarts, and you will attend the school as students. Stay undercover. Keep your ears sharp, any piece of information might be useful. We need to know of all possible threats, as well as possible opportunities. I believe you have been doing exactly such analyses during your military history classes, Annabeth?"

"Yes, but that was country-based,what we're dealing with seems to be an underground society, right? We might have to restructure our model."

"That doesn't matter. A model can be adapted with ease given enough time and information. What matters is whether you're all willing to go and collect that information or not." Chiron had folded his arms across his chest.

"I'm in." Leo stated excitedly.

"You can count on me." Nico agreed, neither his stance nor tone showing any emotion at all.

"Come on Percy, magic might be fun!" Annabeth exclaimed when she saw the expression on Percy's face.

"Sure, he said grudgingly.

"Then Percy and I are in too." With that, she answered Chiron's raised eyebrow. Nico groaned at the remark.

~A Few Days Later~

"When I signed up for this I did not expect having to study magic for two weeks straight!" an exasperated Leo called out when the spell he had been trying fired backwards for what felt like the hundredth time. He fell to the floor, unable to move.

Annabeth lifted her new wand and clearly said "Reparifors!" upon which Leo was able to stand up again.

"It is important to pronounce 'Petrificus Totalus' correctly" Percy told him, accidentally freezing Leo in place once more.

"Oops, sorry" he stated, laughing, copying his girlfriend to undo the spell.

"Not funny, Percy!" Leo shouted, running after the giggling Jackson, trying to tackle him.

"You do know you'll have to do the same thing every single week once we're in Hogwarts, right? We're just trying to get a basic understanding of wizardry before joining the other students. We can't afford to lose our cover." Annabeth called after Leo, who didn't listen, since he was too busy pummeling Percy. She sighed and returned to her "A History of Magic" textbook.

On the evening of the last day before their departure to the United Kingdom and a train station called King's Cross, Annabeth quizzed all of the other members of their "spy team", as they had jokingly started to call themselves. Of course, that ended in disaster. Percy stupefied everything from nymphs to Grover to an angry Clarisse, everything except the poor Will Solace, whom they had asked to be the target.

"Maybe I just don't want to harm someone so nice, " Percy explained, his eyes glittering with amusement when a despairing Annabeth asked what by Zeus' underpants was wrong with him. Nico, who had not taken part in any of their other self-guided lessons, lifted his eyes from the sword he had been sharpening.

"Don't you dare hit on him, Jackson. He's mine!"

Will Solace, supposedly straight, blushed. Annabeth, giving up on Percy, who had taken personal offense to that statement and was now in a good-humoured argument with Nico, moved over to check on Leo's progress. Except for his ability to create flames of all colors and a variety of properties, he was a hopeless case.

The Full Body-Bind Curse backfired once again, his "aguamenti" did not extinguish a small flame but instead soaked the still bickering Percy and Nico through with water. When Leo tried to disarm her, nothing spectacular happened except that a "Leo is cool" flag sprung out of his wand and fell on the grass between the two duelists.

She finally pulled Nico away from Percy, both still sulking in their wet clothes, and asked him to perform multiple simple charms. Some worked out fine, but during the fourth one, a basic levitating spell, he rose the bones of a hundred different animals, turning the field into a graveyard instead of lifting the small dagger that lay before him. Annabeth was done by then. With a moan she declared that all of them were fucked and stormed off to her cabin.

"I dislike agreeing with her, but she is right." Leo stated, suddenly sober. "We're screwed."

"Why can't we have extra time anyways? How are we supposed to learn the stuff they learnt in four years in only two weeks?" Percy exclaimed, starring after Annabeth.

"Every week, more satyrs are gone. You know that." Grover said, with a slightly accusing look in his eyes, his sudden appearance scaring them all to pieces.

Percy pulled his best friend into a hug. "I know. I shouldn't have said that, sorry."

Nico still stared at the floor, at the bones he had pulled from the ground. "Wait, you know all the things we were good at? They're things controlled by our godly parents. In my case, that was bones. In Leo's, it was fire."

"I might agree with you there, death boy, but it isn't like I was good at anything that related to the sea."

"We all knew you're a special case, Jackson, " Leo joked.

"I'm flattered you think of me in such a way. Nico, you have competition."

"Shut up!" Nico said, turning red.

Leo shook his head. "You know, I meant it more in a; you need to visit the mental asylum, way."

"How nice of you!" Percy chuckled. "But we'd better get some rest. Tomorrow we'll have to get up early."

"Always ruining the fun, aren't you," Nico muttered under his breath. However, he'd already started to move towards the cabins.

Percy raised his eyebrows. "I'd tell you to suck my dick, but you might take it too literally." he called after the black figure in jest.

The son of Hades stopped and turned around slowly. "Watch out, I might sneak into your cabin tonight, " he replied, his face dead serious, but his eyes gleaming humorously.

Nico waited for the other two to catch up. The three friends walked down the hills arm in arm, only going their separate ways once they reached the village.

Thanks a lot for reading! If you have any ideas of how I could improve my writing, please consider writing it in a review!

Here's the list of how this fic is different from other similar crossovers, something I myself asked a lot simply because this story has been done so often.

- Voldemort isn't the main/only villain; there's much much worse than him

- There are actual stakes in the demigod world; Camp Halfblood and Camp Jupiter are in direct danger and likely to be destroyed

- There will be HP non-related plot points; such as a Roman civil war in Camp Jupiter

- The HP story will be expanded past book seven and explore new concepts and ideas, as well as turn Harry's world upside down

- Fantastic Beasts series will have a large impact on this story

Thank you so much for reading, see you around (hopefully in the next chapter of course XD)

Fives over and out