AN: So I love Harry Potter and I love Captain Swan and so naturally the next step was to write a crossover.

Gotta admit, I had a lot of fun with this.

I don't own Once Upon a Time or Harry Potter. If I did, I'd have my own ceramics studio.

Enjoy!

Killian Jones' jaw dropped when he first laid eyes on the ceiling of the Great Hall. It was dark blue and dotted with stars, the same as the sky he had been staring at as he and the rest of the first years crossed the lake. Caught up in the beauty of it all, Killian nearly walked into the boy in front of him when the mob of first years came to a halt before the daïs, the professor's table, and a stool with a ratty looking hat sitting on top of it.

Professor McGonagall called for silence and began calling out names.

"Arendelle, Elsa," was the first, a blonde girl who was sorted into Ravenclaw. Next was Blanchard, Mary Margaret, who became a Hufflepuff. One Gryffindor and one Ravenclaw later, two boys in a row were sorted into Slytherin: Booth, August and Cassidy, Neal.

Killian watched as his classmates were sorted, until-

"Jones, Killian," McGonagall called his name.

Nervously, Killian made his way up to the stool and did just as his classmates had done before him, the large hat nearly covering up his nose once it was on his head.

Hardly ten seconds later, the hat had made a decision.

"Hufflepuff!"

Killian grinned and was quick to return the hat to McGonagall and even quicker to hurry over to the Hufflepuff table, where his new housemates were cheering for him and where Mary Margaret and another first year, a boy whose name Killian couldn't remember, were saving seats for their potential housemates.

Craning his neck, Killian looked over at the Gryffindor table, looking for one face in particular. It took a little while, but finally Killian spotted Liam, his older brother (older by two years). Liam apparently had been looking for Killian too, and the brothers locked eyes across the room. Liam was grinning widely and proudly and gave Killian a huge thumbs up that he laughed at. His brother was a dork. Liam got distracted, though, when a new Gryffindor was sorted: Nolan, David.

"Nolan, Emma," McGonagall called out exactly one year later. Killian watched as David's little sister jammed the hat upon her head and he glanced over at his best friend, seated at the Gryffindor table. Killian shook his head at him. He had met Dave's family when he visited them that summer and the boy was stupid if he thought his sister would go anywhere but-

"Gryffindor!"

"Up!" Emma shouted with authority, her hand outstretched over the handle of her standard issue crappy school broom. To her surprise, it jumped into her hand. Looking around at her classmates, the only other person who succeeded on their first try was Slytherin first year, Lily Page.

Killian really and truly despised potions. He didn't have the patience for it. He couldn't stand just waiting and watching a cauldron bubble when there were so many better ways for him to spend his time.

He could be out on the quidditch pitch right now, practicing for the first try-outs he would be allowed to participate in at Hogwarts, but no. Apparently sitting back in his seat and doodling on his arm while his potion brewed was a better use of his time.

"C'mon, Emma, what's the harm in just trying out for the team?" Ruby Lucas, a fellow third year Gryffindor and one of Emma's best friends pleaded with her.

"I don't know, quidditch is David's thing, I don't-"

"Emma, you're good on a broom," Ruby cut her off, "you're a good buyer and do you not remember that time you threw an eraser at Belle's twin's face and it hit her square in the forehead?"

Emma apparently was taking too long to come up with an answer to that.

"Emma, there ate two chaser positions open now that Goodwin and Dallas have graduated. You'd be a great chaser and so would I. We're going and we're trying out for the team," she decided, and as much as Emma wanted to argue, she knew it was pointless.

Two weeks later, both girls tried out, and to their shock and surprise (though Ruby would never admit it), they both made it.

Two years later, a lot had changed. David and Killian were sixth years and both had been given captaincy of their house quidditch teams. (So did Regina Mills, a fifth year and a chaser on the Slytherin team)

Henry Nolan, David and Emma's little brother, had finally started Hogwarts a year previously and was proving to be a talented wizard. Emma and David would boast about their smart little brother, embarrassing the boy until his face was as red as a tomato. But they loved him, that much was obvious to anyone with eyes. The Nolan siblings were close and they would go to the ends of the earth for each other.

Speaking of siblings, Liam Jones had graduated and was starting the Auror training program under the new head of department, Harry Frickin Potter, and was sending Killian letters every other day. Though the younger Jones brother was still a bit lonely without him there in the castle.

So, he turned to David, and the two boys were closer than ever. They were best friends and they shared a lot with each other, for being boys. Though, after they had both been granted captaincy, they had decided no more quidditch talk. At least, no more Hogwarts quidditch talk. They still argued about the Tutshill Tornadoes and the Appleby Arrows for hours on end.

Ema's fifth year had been pretty decent, as decent as O.W.L. year can get. She had a boyfriend who she really liked, she was doing well in her classes, she was made a prefect, and the team was doing great. She did get a few detentions and those may have been said boyfriend's fault, but she forgave him. At least, she forgave him until she was doing her prefect rounds and found him in a broom closet kissing another girl.

Emma spent the summer after her fifth year reeling after the realization that her now ex-boyfriend, Neal Cassidy, had been cheating on her. She didn't know the name of the girl she'd caught him with, but it didn't matter. She felt so stupid.

"And Gryffindor takes the quaffle! That's Nolan, the middle Nolan, mind you, Emma Nolan with the quaffle, speeding down the pitch," Emma caught August Booth's commentary in the outer registers of her mind as she sped towards Hufflepuff's goal posts, Ruby and Robin flanking her. They ducked and wove, dodging the Hufflepuff players until they reached their goal posts and-

"Nice save by Hufflepuff Keeper, Killian Jones, better luck next time, Nolan!"

Emma scowled at Killian, but he only grinned at her as he tossed the quaffle to one of his chasers, a third year named Grace Jefferson. He may be her brother's best friend, but it was frustrating, how good she was at his position. Before Emma sped off in pursuit of the quaffle again, she caught a wink from Jones.

"Nice hit there from Gryffindor Beater, Mulan Fa. Jefferson drops the quaffle and it is intercepted by Lucas!"

Ruby passed it to Robin, he passed it to Emma, and she dropped it back down to Ruby right before she would have collided with Hufflepuff chaser, Graham Humbert. With a grin on her face, Emma watched as Ruby got closer, aimed, and-

"Lucas scores! Ten points to Gryffindor!"

Ten minutes later, the score was twenty to thirty, in Hufflepuff's favor, Emma was really damn irritated by their unfairly attractive Keeper, and Hufflepuff had the quaffle again. And David wasn't able to block it.

"Humbert scores! Ten points to Hufflepuff!"

Damn, now it was twenty to forty. Emma shook herself a bit - she had to get her head back in the game. At any rate, as long as Hufflepuff didn't get one hundred and fifty points ahead, they were golden. Henry was easily a better Seeker than Mary Margaret. Although, Emma acknowledged, she might be a little biased towards her little brother. Just a bit.

"Ten points to Gryffindor, Nolan scores!"

"Nice work, love," Killian said before she left his end of the pitch.

"Thanks, Jones!" she called over her shoulder, grinning at him. Dammit, she couldn't help it, she was flying, she finally scored, and she was in a good mood.

"Oi! Emma!" Leroy Arenberg, a fourth year and one of their Beaters shouted, bring Emma's attention back to the game.

"And Nolan catches the snitch! Gryffindor wins, one hundred and ninety to sixty!" Booth shouted into his megaphone while on the pitch, the Gryffindor team crashed together in a laughing, cheering mob. The Hufflepuff team stayed to congratulate them and then most of them wandered back to their locker rooms, though Killian and Mary Margaret lingered.

Breaking free from the mob of red and gold, David made his way over to his best friend and his girlfriend, followed closely by Emma.

"Good game," Mary Margaret said, a bit grudgingly considering that she and her team had just lost. David laughed and hugged her close, kissing her on the cheek.

"Hey, beautiful," Killian said, sidling up to Emma and slinging an arm around her shoulders. Emma rolled her eyes at him, though she was still grinning - still high on adrenaline from the match.

"Hey yourself," she greeted him.

"Sickeningly cute, aren't they?" Killian said, nodding over at David and Mary Margaret, who were still hugging and making goo-goo eyes at each other.

"Absolutely vomit-inducing," she agreed. "They're even Head Boy and Head Girl, how stereotypically perfect can you get?"

Killian laughed loudly and openly at that, and Emma joined in.

"You played well today, Nolan," Killian said once their laughter calmed down.

"Thanks," Emma said, barely suppressing the blush that was rising in her cheeks. "You weren't so bad yourself."

"Oh, Emma, I'm flattered," Killian said dramatically.

"Yeah, well don't get used to it," Emma said with a little smirk.

A few weeks later, Hufflepuff was back on the pitch, though this time they were playing against Slytherin. Emma, David, and Henry were all in the stands with their fellow Gryffindors, cheering Hufflepuff on.

"It's Scarlet with the quaffle, Scarlet racing down the pitch. Ooh, that's gonna be a solid bludger from Page, but oh! Deflected by Kristoff Bernson! Scarlet passes to Humbert and it looks like he's going for the right-hand hoop - Slytherin Keeper Walsh Oswald certainly thinks so - Humbert scores! It was a feint! That boy is brilliant! Ten points to Hufflepuff, that makes it thirty to fifty in Slytherin's favor," the commentator, a Slytherin boy called Sidney Glass narrated into his microphone.

The Gryffindors and Hufflepuffs, some Ravenclaws too, cheered and applauded.

Killian was having the time of his life. Slytherin may play dirty, but his team was doing well against them. He had saved six goals and counting, Humbert was on a scoring streak, and the stands were practically a sea of yellow and black. Keeping one eye on the quaffle (which was in Jefferson's hands, Humbert and Scarlet on either side of her), Killian looked over at the stands. The first face he picked out was David, waving a Hufflepuff banner, whooping and cheering. The second face was right beside David, her blonde hair spilling over her shoulders and framing the yellow and black scarf that was wound around her neck.

Emma was clapping and cheering, and Killian watched as she lifted a hand to her lips, letting loose a loud whistle before the smile returned to her lips, stretching from ear to ear. God, Killian was in trouble. A cheer rose up from the Hufflepuff stands, louder than before, and Killian's eyes were back on the Slytherin goal posts; Oswald was scowling, but Grace was grinning like an idiot and a chant of Jeff-er-son! Jeff-er-son! had started up in the stands.

"Grace Jefferson scores! Ten points to Hufflepuff!"

"It's Mills coming down the pitch, she passes to Heller, he dodges a bludger from Bernson, he passes back to Mills," Killian listened as he watched Regina barreling towards him. It looked like she was going to go for the left but- no, that would be too easy. Killian watched with bated breath as she drew back her arm and the quaffle and threw- he was right. He went left and he blocked it.

The Hufflepuff stands were cheering, but one voice rose above the others.

"Alright, Killian!" the voice shouted, and he looked over to the stands to see Emma punching the air and whooping, cheering him on.

"It looks like Booth has spotted something- oh, so has Blanchard! They're diving, they're neck and neck, Blanchard pulls ahead! She's closing in, Blanchard catches the snitch! Hufflepuff wins and with the score being two hundred and twenty to sixty, Slytherin is out of the running for the house cup," Glass narrated, though he sounded awfully disappointed at the last bit.

Emma cheered at the top of her lungs, and it was Emma who led the charge of Hufflepuff supporters out of the stands and down to the pitch, just as the team was touching down. Grinning from ear to ear, Emma ran to Killian and flung her arms around his neck, hugging him tight.

He was laughing, a smile on his face, and before Emma even realized what she was doing, she was gripping the collar of his quidditch robes and crashing her lips against his own. Killian was surprised to say the least, but he dropped his broom and took Emma into his arms, holding her close and kissing her back. And Merlin, did he kiss her back. Emma's knees were weak beneath her and when they broke apart, she was still grinning, even more so when Killian rested his forehead against hers.

"That was unexpected," he remarked, his voice all breathy and low in a way that Emma had to say was downright dangerous.

"Go out with me?" Emma asked, and even she had no idea where it came from, but it felt damn right.

"I thought you'd never ask."

Thanks for reading! If you liked it, let me know in a comment!

I may or may not write an epilogue to this at a later date.