My first crossover, and I had so much fun with this that I completely put off a bunch of homework and other fanfiction that I have to write, just to work on this pretty much all night. I don't regret it one bit. I just can't believe I haven't written more crossovers between these two series before :) I really hope you all enjoy!

Twenty-year-old Annabeth Chase was utterly lost in the streets of London.

She'd memorized the layout of the city. She knew precisely where she was supposed to be, though Percy, who had come with her on this architectural experience, was nowhere to be seen (she had a hunch he was busy eating up the candy store they'd seen). And to top it off, she'd somehow lost her wallet.

"Oh, gods," she muttered to herself. "If Chiron could see me now."

It was that moment that Annabeth suddenly found herself in front of a little worn pub that, she was 100% certain, wasn't supposed to exist. At least, according to the multitude of maps she'd studied on the plane.

It was called the Leaky Cauldron, she noted. A funny name.

Looking around, she saw that none of the people walking past appeared to notice the pub. In fact, the more she stared at the old little sign, the more it seemed to… fade. She tilted her head. The building appeared to shudder back to life. But when she once more stared at it directly, it became very fuzzy.

Annabeth warily stepped away. It wasn't just the look of the pub that creeped her out. It was the funny shivers racing down her arms as she stood near the door. It was almost as if… as if this was a world she was not supposed to touch. And Annabeth, despite her curiosity, didn't really want to.

She was almost about to leave when she saw a hint of messy black hair through the grubby window. She peered closely. Wasn't that… Percy she saw? He had the same thin but muscular build, the same dark hair -

Annabeth impulsively reached for the door and strode into the Leaky Cauldron. That was her first mistake.

She didn't know what she expected, but she certainly didn't expect the sudden sickness that jabbed into her stomach and threatened to come up and out. Annabeth had gotten fatal wounds before, but this was something different. It was almost as if it was inside her, writhing through her bloodstream and pulling at her heart and stomach.

She crumpled to the floor, gasping and saying stuff like, "Percy, you idiot," and "Oh Zeus, have mercy!" and a bunch of other gibberish that she would probably regret later - but suddenly there was a head of black hair and another one with puffy brown hair, and she was somehow being lifted into a chair, but she couldn't feel any arms holding her.

"Are you okay?" asked someone, but Annabeth could only point weakly at her heart, which seemed it was going to burst.

"Here, give her this!" shouted someone else, and suddenly someone was forcing a thick liquid down her throat.

She could feel the drink enter her system and almost immediately stop the clenching of her heart. Ambrosia or nectar, she thought, could have done better, but her body began to relax, and in no time, Annabeth was standing and pulling out her Celestial bronze dagger.

"Who are you?" she all but yelled. "And what have you done to me?"

The faces of the few people around her were alarmed, but the moment she had her dagger out, they retaliated, yanking out… sticks.

She briefly wondered if this was some prank that was going on without her knowledge, if Percy was playing a joke on her. Maybe she was just hallucinating, and they really had little guns in their hands. Maybe they'd drugged her.

The man with the black hair stepped forward, and she almost screamed out, "Seaweed Brain!" because he had the same messy black hair and green eyes that her boyfriend did.

He had a completely different face, though. And he wore glasses.

Annabeth wondered whether she could quickly take out the three people standing in front of her and get out of there. The knife could possibly not be of any use (they looked very normal and mortal), but she could surely take out at least the black-haired man and the brown-haired woman through hand-to-hand combat. She wasn't all too certain about the tall, lanky redhead, though.

"I'm Harry Potter," said the man, his stick still clutched in his fist and pointed at her. "And you are?"

She hesitated before saying simply, "Annabeth."

The woman suddenly blurted out as if she could not stand it a second longer, "What is that?" She was staring at Annabeth's knife with a look of wonder and apprehension, one that Annabeth knew all too well came from a desire to learn.

Perhaps she was a daughter of Athena, Annabeth dared hope, which was why she tested, "My dagger." She waited for the woman to reply, to show that maybe she was a demigod too.

"What's it made out of? It looks rather… different." The woman tightened her grip on her stick and stared openly at Annabeth. "Who exactly are you?" she asked sharply.

Annabeth almost smiled, because here was a woman, Athena's daughter or not, who was obviously very wise. "Annabeth Chase," she offered in full, though she did not lower her knife.

"Where are you from?" the redhead man suddenly said, pushing the woman behind him in a protective manner. "Where's your wand?"

"My what?"

"Your wand," the man insisted. He squinted at the dagger in her hand. "Is that it? Did you disguise it?"

"Of course she didn't, Ron," said the woman, making her way back in front of him. She stepped closer to Annabeth, and Annabeth saw, with some disappointment, that she looked nothing like Athena. For one, she had brown eyes. "Can't you see that aura it's giving off?"

Annabeth stared at her. "Its what?"

"Giving off that little bronze aura, can't you see it? I'm Hermione Granger, by the way." The woman lowered her "wand" and stuck out a hand, apparently convinced Annabeth wasn't a threat after all.

It was strange because even as Annabeth shook Hermione's hand, her dagger was still pointed at Ron and the man named Harry.

Hermione noticed as well, and said to the men, "Oh, put your wands down, can't you see? If she wanted to hurt us, she already would've."

"Hermione," said Harry, "I do see that aura you're talking about, and I don't like it. She could be dangerous."

"She is right here," Annabeth muttered irritably before raising her voice. "And while I won't argue that I can be dangerous, I'm honestly just passing through. I thought I saw my boyfriend in here, but it was you," she addressed Harry before turning to Hermione. "Now I'd really like to get going, but I'm just wondering what in Zeus's name you or the pub did to be when I walked in."

"What do you mean?"

Annabeth gestured towards her heart. "The whole clenching thing. Is it customary for that to happen?"

"What on earth are you talking about?" asked Ron.

"When I walked in, it was like… there was something inside of me trying to tear me up. It started at my stomach but then it went to my heart, and it felt like the whole pub was pushing against me. I don't really know how to describe it," she said truthfully. "And then you gave me that" - she looked at the empty flask on the table - "and it got better."

"It's a pain-relieving potion," said Harry, but he was staring at her oddly.

Ron was looking at her weirdly as well. "Did you Apparate here?"

"Did I - what?"

Hermione cut in, her eyebrows furrowed. "Which entrance did you come in?"

"The only one there is," Annabeth said, puzzled, as she looked around the bar. There really didn't appear to be any other entrance around, although there was an open door in the back that led to some sort of brick wall Annabeth couldn't really see.

"So the Muggle one," Ron frowned.

"I'm sorry, but I have no idea what you're talking about. What's a muggle?"

As soon as she asked this, the three in front of her seemed to realize something at the same time. All of them acted very differently, though.

Hermione began to pace and say very quickly, "But how did a muggle get through, how did she see it, are the wards too old, should we do something about this-"

Ron, the redhead, started to let out a stream of curse words that Annabeth found rather impressive.

And Harry, the only one who retained a sense of calm, heavily sat in a chair and said seriously, "Just who are you exactly?"

The other two quieted as Annabeth hesitated. It would be unnecessary to tell these mortals more than they had to know… and yet she had the strange feeling they weren't just mortals. There was something about them, about their stick wands, about the way they said "muggle", that Annabeth wasn't all that certain she trusted.

"I'm Annabeth," she began slowly. "And I'm from Long Beach in the United States. I'm here on a short visit to different parts of England and Scotland." That should be enough. She changed her tone to an inquisitive one. "Now who are you?"

"I'm Harry, he's Ron, and she's Hermione, as you know," said Harry. His green eyes bored into hers, and she knew he wasn't going to give up so easily. "We're all from here."

She might've been able to hold her ground if she hadn't been so curious to know what was going on. "What's a muggle?" she blurted out.

"What's that dagger made out of?" Harry retorted.

And even though Annabeth could think of two ways she could possibly get out of this one, she had a feeling Harry had already worked out one of her greatest weaknesses - the curiosity for knowledge. Feeling like a fool for being so easily manipulated, even if the threesome was at least likable, Annabeth said grudgingly, "How about an exchange of knowledge? You tell me about your world, I'll tell you about mine."

"Agreed," said Harry after a moment's consideration. "And as long as you keep it a secret, we'll do the same."

"Harry, I'm not sure about this," whispered Hermione, just as Annabeth suspected she would. "What if she really is just a muggle?"

"She's not," said Ron.

"She's not," Harry repeated, nodding. "Couldn't you feel it? Right when she walked in, there was this wave of something different."

"Yes, I did feel something strange in me," murmured Hermione thoughtfully. She sighed. "Alright. But we have to put a charm after, to make sure she doesn't tell anyone."

And so began the exchange of information.

Annabeth could hardly believe what they told her. Apparently, Harry, Ron, and Hermione were all magical, meaning that with their sticks - wands - they could do magic. Any type, too. They didn't need to be Poseidon's son to create water (as Harry demonstrated). They didn't need to be Aphrodite's daughter to attract people (they had drinks called potions that could do all sorts of things). All they needed was to do some swishes with their wands and say the spell and that was it.

They told her about the magical world, how they were in one of the well-known pubs in Wizarding London, and how that would explain why she'd never seen the building on a map before. They told her about Hogwarts, which sounded absolutely wonderful and a bit like the dream school she never really went to. They told her about dragons and broomsticks and phoenixes and things she could relate to through mythology and experience.

And in return, she told them about Camp Half-Blood. She told them about the 600th floor of the Empire State Building. She told them about her mother, how she was Athena's daughter. She told them about the Big Three gods, and she told them about golden drachmas and Iris Messaging.

She told them a little bit about herself and Percy and their adventures. She told them about celestial bronze and Imperial Gold and Camp Jupiter. She told them about hellhounds and Furies and how lightning would boom when Zeus was angry, how Camp Half-Blood was hidden from regular mortals, how she'd been there for years now, returning to help train demigods. She showed them her bead necklace, which she always wore.

"That's bizarre," Ron said incredulously when she finished. "You can't actually be the daughter of a goddess. I mean, they don't exist, do they?"

"Ron!" snapped Hermione before Annabeth could retort. "Plenty of people wouldn't believe that magic exists either, but it does, doesn't it?" She turned to Annabeth. "It's fascinating that this is all happening just across the ocean. Do you - have you ever seen any American magic schools there?"

"No," said Annabeth, shaking her head. "This is the first I've had contact with magic."

Harry spoke up. "Well, at least your experience with mythological creatures-"

"They're not really mythological-"

"Fine, but anyway, at least your experience with them would explain why even though you're a muggle, you're able to see and come into here. It's also probably why your stomach started hurting. I don't think you're really meant to be here. No offense," he hastened to say. "I just meant… well, er-"

Annabeth met eyes with Hermione and the two rolled their eyes at the same time. "Men," Hermione mouthed, and Annabeth grinned.

"I think I've got to get going," she said apologetically after a little more talking. "I have to find Percy."

"Of course," said Harry, and the three got up along with Annabeth, walking to the entrance of the pub that led to the muggle world.

Before she could step through the doors, Harry put a hand on her shoulder. "Annabeth."


"You have to promise you won't tell a soul about magic. You're different from most muggles, but you're still a muggle. Things like this shouldn't be spread, especially in your… world."

She readily agreed, because she understood exactly what he meant. "But you three can't tell anyone about what I've told you either. It should be okay because you're not demigods yourselves, but the monsters might find you anyway." She abruptly cursed, which caused the three adults to take a step backwards. "I shouldn't have said anything. Now I've possibly endangered all of you-"

But the three didn't seem to be taking her as seriously as she would have liked - Harry even smiled. "Don't worry," Ron assured her. "We'll be fine. Just make sure you don't tell anyone that you've told us about it all. Greek mythology…" he trailed off wonderingly.

"It's not mythology," Annabeth and Hermione said almost at the exact same time. "And I won't," said the former, putting her hand on the door. "I guess this is goodbye."

"Yeah. Good luck finding your boyfriend," smiled Harry.

"Maybe we could write letters or something," Hermione offered, looking a little pained, as Annabeth felt. Looking into Hermione's brown eyes made Annabeth feel like she'd known her for years; she was so like a daughter of Athena that Annabeth almost felt as if she was leaving a sister behind.

She was about to vigorously nod and agree, when she remembered that it wouldn't do to send letters, not when it would complicate things and put the threesome in even more danger than necessary. So she bit back her tongue and said, "I'd love to, but I'm afraid the owls might scare some of the monsters hanging around New York. They might eat them," she joked (though she realized it was true).

The three seemed to understand what she was really saying, and nodded, though Hermione looked a bit crestfallen at that. "Alright. Well, then maybe we'll cross paths again."

"Maybe," said Annabeth, but she didn't believe it. "Until then."

She left the Leaky Cauldron with a final wave to Harry, Ron, and Hermione, knowing she could never see them again, knowing she could never risk it.

Her heart felt heavy as she stepped back into the flow of people - muggles, to wizards and witches - brushing past. Annabeth cast one more glance back towards the Leaky Cauldron, where she'd discovered another huge society hiding from the normal people of the world.

She stopped in her tracks and stared at what she was seeing - rather, what she wasn't seeing. The pub was gone, as if it had never been there. The buildings that had been on either side of it were now next to each other, as if there hadn't just been a pub in between them.

Annabeth's mouth parted as she openly stared at nothing. It was gone. It was really gone.

It was just like magic.

Written for January Scavenger Hunt: Write a crossover.

Hope you enjoyed it :)

xo Summer