This is my first crossover story! I promise you, it's actully good. I made sure of it. Thank you so much to my fanfic friend Bookgeek14 who has been my critical eye for this story! If you don't like it, I'm telling you it gets better! Please review and let me know if you like it!

Disclaimer: I do not own Harry Potter or Percy Jackson.

Al Potter sat outside at a restaurant, surrounded by his family. The Weasley-Potter Clan had taken a trip to San Francisco, California, and they had stopped for lunch on the Embarcadero. Al's father, who was the infamous Harry Potter and head of the Auror Department, had important business to do with some American wizards, and they had conveniently decided to make it into a family vacation.

Al certainly didn't mind his family. He loved them, of course. But when the family was as large as his, it often became tiring. His younger sister Lily was talking animatedly to his cousin Hugo. His older brother James who had recently graduated from Hogwarts was telling their mum about his plans to take over the joke shop with their cousin Fred. Al sat next to his cousin Rose, and next to her was his best friend (and Rose's boyfriend) Scorpius Malfoy. After Scorpius' parents were killed by some vengeful muggleborns during his first year at Hogwarts, the Potters had pretty much taken him in as their own. As a result, the three of them had become pretty much inseparable during their time at school.

They were coming up on their seventh year at Hogwarts this year. There had been a lot of commotion at the end of their sixth year when a mob of unknown mythical creatures tried to attack the school, almost killing 50 first years. Since then, the Aurors had been working non-stop trying to figure out how these monsters got to London and why the magical boundaries of Hogwarts weren't stopping them. They had contacted some American wizards who said they had seen similar creatures in San Francisco, and so Harry was sent on a mission to figure out where they were coming from.

"There has to be an epicenter," Hermione was saying to Harry. "One place the creatures are all coming from. I did some research and found a few Wizarding schools here in California. It's possible they are getting similar attacks."

"Not necessarily," Ron said. "These magical beasts haven't just suddenly decided to become vicious. Normally they could be completely harmless. There's got to be someone behind the attacks, luring the monsters to Hogwarts."

Harry nodded. "Let's ask the Headmaster of one of the American schools for a meeting. Talking to them can't hurt."

Hermione handed him a piece of paper. "Here's the list of schools that are closest to where we are now. I've found that many of them are much newer than most of the ones in Europe. Did you know that there are some that were founded as recently as 1950?" As Hermione began spewing out facts about Californian Wizard history, the conversation moved to the magical innovations of the newer American schools.

Now just to be clear, Ron and Hermione were not Aurors. Hermione worked at the Ministry and Ron helped George run the joke shop. Harry had a group of official Aurors with him, but whenever anything became serious, the Ministry would let him confide in his family for help. When it came to the Golden Trio, they could accomplish pretty much anything if they worked together.

"Do you know what you're gonna do after school, little bro?" James asked Al, who had been listening to his father discussing with his aunt and uncle.

He turned to his brother. "I might go into journalism," Al told him. "I'd like to work for the Daily Prophet."

"Aw, you know they're completely corrupt!" James waved a hand at him. "I thought you'd follow Dad's footsteps and become an Auror."

"I might," Al said, "but I think that kind of thing is more for Scorp than for me. And the Daily Prophet is much less corrupt than it used to be."

Harry never kept very much secret from his family, even if he was supposed to. Ginny always asked about the Auror work and Al and his siblings were never left out of the conversation. Because of this, Al always felt very informed about what was going on in the Wizarding World. Although Scorpius planned to become an Auror when he left school, Al thought it would be more interesting to go into journalism. That way, he could learn first hand about all the intriguing stories in the Wizarding World, and then share them with others.

"Al! Al are you listening?" Rose snapped her fingers in front of his face. Brushing away his thoughts Al turned his attention to Rose and Scorpius.

"Sorry, what?"

Rose rolled her eyes. "Scorpius and I were talking about the last Cannon's game," she said, "I asked if you remembered the score."

Rose, like her father, had a large obsession with Quidditch. She idolized Ginny, who played Chaser for the Holyhead Harpies. She even rivaled Scorpius, the Gryffindor seeker, on a broom. Al was decent at Quidditch, and often played with his family, but never tried out for the school team. Although everyone told him he could easily make it as Chaser, he preferred to cheer on his friends.

"No," Al shook his head, "I don't remember." As Al joined in a conversation with Rose and Scorpius about Quidditch, he suddenly noticed something out of the corner of his eye. Looking closer, he saw a large, black, dog-like creature standing on the pier. He immediately thought of the stories his father told him about his godfather Sirius Black who was a secret animagus and could transform into a large black dog. But he had died years ago, and this was not just a dog. It was probably the size of a truck, and it bared it's razor-sharp canines menacingly at them.

Al gasped and reached for his wand. Rose and Scorpius followed Al's gaze. "Bloody hell!" Scorpius said, "What is that?"

The conversation at the table stopped and the adults turned around to look at the creature as well. They stood up and cautiously gripped their wands.

"Wait," Harry said holding up his hand. None of them moved.

"We'll have to surround it," Harry decided. "Ginny, you approach from behind. Ron come from the left, Hermione come from the right; I'll take the front."

"Dad, what about us?" James asked.

"You are going to stay here," Ginny said, giving them all a stern look.

"But-" James protested. Ginny glared at him warningly which shut him up.

"If anything happens, you back us up," Ron whispered to them. Hermione glared at him. "Of course, we don't expect to need it," Ron added, winking at them. Al smiled.

The four wizards left the restaurant discreetly and, pulling out their wands, approached the creature from all sides. All at once, they shot four stunning spells at the giant dog's head. On any typical magical beast, that should have been enough to knock it out, but the spells only seemed to make it angrier. The dog growled dangerously.

They were not the only ones aware of it though. From the restaurant, Al watched two teenagers about his age cautiously approach the creature as well. The girl had curly blond hair and the boy had shaggy dark hair. They both wore orange t-shirts and each of them held a long metal object that glinted in the sunlight.

"Who are those kids?" Scorpius asked. "They've got some pretty large wands," he said.

"They're not wands," Rose said. "They're swords. They're like large knives that muggles used during the Middle Ages to fight battles."

"Well if they're muggles, they're the only ones who seem concerned," Al said.

It was strange. The dog thing did not seem to be disturbing anyone else on the pier. In fact, the people walking by seemed completely oblivious to it.

"That's odd," Scorpius said. "Do you think they're wizards then?"

"Maybe American wizards use swords," Al said, though he was still highly doubtful. Was this what Aunt Hermione meant about American wizards being innovative?

They watched as the dog monster snapped at the boy and he dodged it's teeth by millimeters. The girl must have said something, because the monster turned abruptly away from the boy and lunged at her.

The muggles on the pier could clearly tell there was something going on. They were running and screaming and causing a commotion. But they also seemed confused. Al had no clue what they thought was happening, but he got the feeling they didn't see two teenagers fighting a monster.

As the girl rolled away from the monster's jaws, Hermione tried shooting another spell at the monster. Again, the monster was not affected. Then, something even more bizarre happened. The harbor, which a moment ago had been still, was now creating huge waves like it was in a storm.

"Are they doing that?" Al asked, pointing to the rough water.

"That takes some serious magic to make an entire bay move to your command," Scorpius said. He looked nervously at the scene before him.

"Do you know about it?" Rose asked.

"Well," he said, shifting uncomfortably, "when I was young, my father told me a little," he turned to look at them. "The ancient pureblood families, even older than mine, were powerful enough to use very complex wandless magic. Using wands did not actually become necessary until the Middle Ages, after the fall of the Roman Empire."

"So are you saying that those kids are using ancient, wandless magic?" Al asked, astonished. "That can't be. Their sword things must be a special kind of wand or something. No one is that powerful!"

"No, I think he's right," Rose said. "I remember reading about ancient magic in Hogwarts, A History. The purebloods used to be stronger and more powerful. Wizards lost a lot of their magical abilities after the Roman Empire crashed and had to relearn to control it with wands. Do you think... Is it possible that there are wizards who still have ancient blood in them?" she asked.

As the water crashed onto the pier, blinding the dog, the girl stabbed the monster in the chest. The dog looked slightly alarmed, and then suddenly it disintegrated, dust scattering along the pier. The water, washing away the dust, retreated back into the harbor and the bay was once again still. Al searched for the two kids who killed the monster, but they were gone.

"I think," Al said slowly, "We may have found a way to stop the attacks on Hogwarts."