Author's Note: Crossovers are, by definition, AU. This one takes place during season 2 of NCIS: Los Angeles and during Harry's first year at Hogwarts. Purely for my convenience, I've moved the events of Harry Potter and the Philosopher's/Sorcerer's Stone forward in time to make them contemporaneous with season 2.

I'm following Harry Potter and the Philosopher's/Sorcerer's Stone book canon almost exclusively, with brief forays into non-book sources (i.e., the movies, Pottermore, fandom tropes, etc.). Basically, if it's not in that book, it doesn't exist unless it shows up in this story.

As always, all rights in this work are hereby given to the respective copyright owners of NCIS: Los Angeles and Harry Potter and the Philosopher's/Sorcerer's Stone.

CHAPTER ONE

As usual, G Callen was the last to leave the bullpen at the NCIS Office of Special Projects, and the reports he had to complete as a lead agent were only a part of the reason for that. A lack of anyone waiting for him at home was a larger part of the reason he left so late, though he'd never admit it aloud.

On this Thursday evening, everything was properly in its place, and G smiled to himself as he turned for the exit, stopping in his tracks as he realized he wasn't alone. Hetty Lange, Operations Manager, sat at her desk, scowling at … well, nothing that he could see.

"Good night, Hetty," he said, and she visibly started. Whatever had her in a temper must be something big.

But she recovered almost instantly and looked up at him with an expression that was almost pleasant. "Mr. Callen, would you remain for a moment?"

"Sure." Although G knew better than to pry into any of Hetty's secrets, sometimes she shared them with him. Tonight might be one of those times.

He was only mildly surprised when she picked up the phone on her desk and dialed an internal extension.

"Ah, Ms. Jones," she said into the phone. "I'm glad you're still here. I will join you in a moment."

She hung up the phone and G merely gestured for her to precede him upstairs to the operations center.

Nell Jones wasn't alone in Ops, and Hetty cleared her throat to catch the attention of the handful of others who remained. "I believe the workday is over."

G hid his amusement as the remaining techs and analysts shut down their workstations with a speed suggesting they were being timed.

"Nell?" Eric Beale prompted when the analyst in question remained seated. He looked far too much like an eager puppy, G thought.

"I've asked Ms. Jones to remain," Hetty said, and that was all it took.

"Oh. Well, okay, then. Good night." Eric was gone before G could do more than wish him a good night.

Once the room was clear except for the three of them, Hetty said, "Ms. Jones, lock down the room, please."

Nell's eyebrows flew up, but she said nothing as she tapped a command into her computer. Seconds later, the secure doors slid into place and G felt a subtle hum of power thrum through the room as stronger-than-usual electronic security measures engaged.

Then Hetty turned to him. "Mr. Callen, secure the room, please."

G knew his own eyes widened at the order, but he turned and took three steps to a small stone embedded in the wall beside the door.

He drew his right index finger across his left palm, not even wincing at the hiss of pain that followed it. Blood welled and he pressed his palm to the stone.

"Locus ab secure," he said, and a wave of magical energy swept across the room. Hetty could have done the same - like him, she was Romani - Gypsy - and Romani magic was the hardest magic to overcome, but he was King of the Romani, and his magic was the hardest of all.

With a thought, he healed his hand and removed every trace of his blood before turning to face two of his favorite women.

"One might call that overkill," he observed.

"You should know that there is no such thing," Hetty told him, but he made no response because his attention was caught by Nell's expression.

"Something wrong, Nell?" G kept his question casual, despite what he believed was a solid working relationship between them.

"No," Nell said. "Not really. It's just - your magic feels … well, slippery."

"I'm Romani," G reminded her. It wasn't the entire truth, but it was as much as he was willing to admit to her. She'd been with NCIS a little under a year, and while he trusted her skills with a computer and a wand, he wasn't yet ready to trust her with the whole truth of his heritage.

Nell appeared to accept his explanation, though she was still frowning just a little when she turned to Hetty. "So what needs all of this secrecy?"

"Harry Potter."

G blew out a breath. "Oh."

Nell's expression turned confused. "Who?"

G looked to Hetty, and she nodded once, so he gave Nell the bare facts. "About ten years ago, Wizarding Britain had a sort of civil war. A misguided wizard calling himself Lord Voldemort and styling himself a dark lord set out to subjugate everyone who didn't acknowledge him their sovereign. He was defeated when he attacked the Potter family - James, Lily, and their fifteen-month-old son, Harry. James and Lily Potter died in that attack, and Voldemort was … well, some say killed, some say defeated. Whatever the case, he hasn't been seen since."

"And the baby? Harry?" Nell asked.

"Also not seen since that night, though by all reports, he not only survived but was instrumental in Voldemort's defeat," G said.

"More pertinently," Hetty said, "Lily was my goddaughter, and she asked me to be Harry's godmother as well."

"But - you said no one's seen him for ten years? How is that possible?" Nell asked.

"I'm not entirely certain," Hetty replied. "By the time I got to the Potters' house in Godric's Hollow, Harry was gone, and his godfather arrested for betraying the Potters to Voldemort. To make a very long story sufficiently short, I searched for Harry for a long time, to no avail."

"Knowing you," G said, "you did something else, too."

"I did," Hetty agreed. "I visited all the magical schools in Europe and put a notification spell on them all so that I would be notified if Harry attended any of them."

"Just Europe?" Nell asked. "Why not the US? Or anywhere else?"

"Wizarding Britain tends to be insular," Hetty replied. "The likelihood that they would have hidden the boy many believe to be their savior outside of Britain was vanishingly small. I added the notifications to the other schools in an abundance of caution."

"Because there's no such thing as overkill," G said with a small smile. Then, "I assume he's tripped one of your notifications?"

"He has," Hetty agreed. "He's attending Hogwarts School of Witchcraft and Wizardry in Scotland."

Nell immediately turned to her computer.

"No, Ms. Jones," Hetty said. "I know all about the school. James and Lily attended it, you see. I taught there, briefly, as well."

"So - what do you need us for?" Nell sounded even more confused than she looked, but G got it immediately.

"Search and rescue," he said. "Or maybe just the wrath of Hetty?" Though there was nothing just about Hetty's wrath when it was unleashed.

"Why not both?" Hetty smiled a predator's smile. "Specifically, I intend to rain hellfire and brimstone down on those who stole him from his rightful guardians, and then see to it that he is well taken care of."

"How can I help?" G asked. Nell echoed the question only half a second later.

"It is a lot to ask of you," Hetty said, "even though you are my magical heir -" she nodded at G - "and my adoptive heir -" she nodded at Nell.

"Hetty," G began, barely glancing at Nell to confirm her agreement, "we're looking at kidnapping of a minor child, at the very least. Of course we'll help."

"I appreciate your willingness to help, but before you go any further, you should be aware of the worst that might be asked of you."

"Shoot," Nell said.

"In the worst case, I could be denied custody of Harry because of my age," Hetty said. "In that event, I would petition that custody be given to the two of you as my heirs. You would, in effect, become Harry's step-parents."

"I can't speak for Nell," G said, "but I'll do it."

"I - well." Nell blew out a breath. "I can't say I wanted children just yet, but it sounds like this kid's been through it. If I can help, I will - even if it means getting a… how old is he now?"

"Eleven," Hetty said.

"Okay. Eleven. I can work with that." Nell still looked somewhat uncertain, and G couldn't blame her - he felt the same way. "What's the plan?"

"I'll face down the Wizengamot itself if I must, to see Harry safe," Hetty said. "But to do that, I'll need as much information as you can find. Search the mundane world as well as the wizarding world."

"On it," Nell said, and now she turned to her computers with a purpose.

"I'll reach out to my contacts in the ICW and the FBMI," G said.

"Thank you both," Hetty said, and G didn't think he'd ever heard her more sincere.

Almost two months later, they met in the ops center again, also under the strictest security measures. G was grateful they had time to thoroughly prep for the assignment, but at the same time, he wanted to rush off and save a child who might somehow be in danger.

Hopefully, this meeting meant that they were close to satisfying that urge.

"What have you found?" Hetty asked.

G gestured to Nell. "Ladies first."

"You were right that he was hidden in the mundane world," Nell began. "It took some searching, because searches for him didn't come back under his own name."

"How's that possible?" G asked.

"Some very impressive shielding spellwork," Nell told him gravely. "Whoever hid him wanted him to stay hidden."

"How did you find him?" Hetty asked.

"I did a family search," Nell said. "That led me to Lily's sister, Petunia, and her husband, Vernon Dursley."

Hetty's lips pinched into a frown. "And?"

"And when I started searching on Harry Dursley, I got a few hits," Nell said.

"Did these Dursley people adopt him?" G asked.

"I didn't find a record of it," Nell said.

"They wouldn't have adopted him," Hetty said. "Not without someone putting great pressure on them. Lily's family was mundane - Petunia hated magic. Even if she were somehow to agree to raise Harry, she would never have adopted him."

"As I said, some impressive spellwork," Nell said. "In effect, the records were created under the name Harry Potter, but only turn up on searches for Harry Dursley. I'd really like to meet the person who designed that …" She shook her head. "Back on topic, Harry attended primary school and I found a record of his admission to a public secondary school, Stonewall High. Besides a birth certificate, and records of required immunizations, that's all I found."

"Bugger," Hetty muttered. "Mr. Callen?"

"My contacts at the ICW didn't have much to add," G said. "The ICW wasn't called in during or after the war, so the information they have is based on news reports published in the Daily Prophet, and a few reports from hit wizards who were stationed there at the time. None of them seem to know what happened to Harry Potter after the night his parents were killed."

"Bugger," Hetty repeated, more forcefully.

"But," G continued, "that very fact set off alarms, and they reactivated my commission, specifically for the purpose of investigating Harry Potter's welfare."

"That could be useful," Hetty said.

"There aren't many situations where having a hit wizard at your back isn't useful," Nell observed.

"Sometimes having the skill but not the license is more useful," G countered. "But for this, I'll take the license."

"I also looked into child custody laws," Nell said. "As his godmother, and his mother's godmother before him, you have a strong claim for custody. Not as strong as a blood relative, but still pretty strong. Having Callen and me as backup will only make your claim more persuasive. So I prepared guardianship and adoption papers in all of our names. They'll still have to be officially approved by both countries, but all the preliminary steps are in place."

"Excellent work, Ms. Jones."

"What else can we do?" G asked.

"Having a stable home is also important," Nell said. "My apartment's only a one bedroom, so I'm looking for something bigger -"

"Use my house," G said. "Three bedrooms, two baths, a decent backyard."

"Are you sure?" Nell asked. "I mean - I know you value your privacy."

"A child's health and welfare is more important," G said. "Believe me - I would know."

Nell glanced between him and Hetty, then met his gaze again. "If you're sure?"

"I'm sure," G told her.

Nell's expression suggested she was still uncertain. "I've heard you don't have any furniture?"

"Why should I? I can conjure anything I need."

"Thus leaving a trail for any magical to follow."

G grinned at her. "Romani magic can't be traced. It's one reason we're hated so much."

Nell's uncertainty switched to surprised fascination. "It can't?"

"Mr. Callen is partly correct, Ms. Jones," Hetty said. "Only another Romani can trace Romani magic. And even that takes great skill."

"You might feel differently, and that's fine," G told Nell. "I'll keep my old bedroom - no furniture in there, please."

"Um - okay." Nell looked a little shell-shocked. "How will I know which one's yours?"

"My name's carved in the closet door," G said dryly, and she looked torn between laughing and crying. He turned to Hetty before Nell could decide which reaction she was going to indulge. "What else?"

"I'm going to Britain," Hetty said. "I want to have everything arranged, legally - including the approvals for guardianship - before I march into Hogwarts and find out what's happened to my godson."

"We don't know that anything's wrong," Nell pointed out. "He could be okay."

"If he is, then all is well," Hetty countered. "But if he's not, I don't want those old codgers in the Wizengamot to have a leg to stand on if they try to keep him from me."

"You're not going alone," G said.

"Of course not," Hetty said. "As Ms. Jones pointed out, having an ICW-trained and licensed hit wizard at my back is a good thing. Having said that, we'll travel separately. There are a few meetings I need to have where you won't be able to join me."

Nell's frown matched G's own as he asked, "Are you sure?"

"Absolutely certain," Hetty said. "While I do that, you can ask around magical London and Hogsmeade."

"Hogsmeade?" G repeated.

"Magical village near Hogwarts," Hetty told him. "Find out what the British wizarding community knows about Harry. And get us rooms at the Three Broomsticks."

Even before G acknowledged the instruction, Hetty was turning to Nell. "I'll give you an account to charge whatever you need to set up the house for Harry. Extravagance is not necessary, but neither is miserliness."

"Of course," Nell said, as though she knew exactly what Hetty meant. Then again - maybe she did. The two women seemed to understand each other almost instinctively despite their relatively brief acquaintance.

"Thank you again," Hetty said. "Mr. Callen, I will see you in Hogsmeade on Monday."

G knew a dismissal when he heard one, and it was the work of a moment to dispel the wards he'd set earlier.

He started to follow Hetty from the room, but Nell's quiet, "Callen?" held him back.

"What is it, Nell?"

"This - just all of this," she said. "I feel like I'm barging in on your life, and -"

"You're not," G assured her. "If you were, I wouldn't have offered my place. Besides, we don't even know for sure we'll need it yet."

"We will," Nell said. "No, I don't have the gift of divination, but sometimes, people in my family just know things, and I know we'll need your house - or a house. So - I'm sorry."

"Nell." G rested both his hands on her shoulders, and she looked up at him. "I'm sure the others have told you stories - how I don't sleep much, and I do things like take toasters apart when I can't sleep."

"You do?" Nell looked surprised, but not unhappily so. "I clean out my closet."

G chuckled. "Sounds like a good fit." Then he sobered. "I should be apologizing to you, because I just decided that for you."

Nell studied him for a long moment. "How about we each accept the other's apology, otherwise we'll be here all night?"

"Deal." G smiled at her and started to leave again, stopping abruptly. "You need to come by so I can add you to the wards."

Nell blinked at him. "You have wards on your home?"

"You don't?" G countered.

"Well, no - I mean, the building has wards, but I didn't add any to my apartment."

"I'd suggest you do, but if you're moving to my place, you don't need to."

"Right." Nell blew out a breath, then met his gaze with a glimmer of amusement. "War wards?"

"Not nearly as lethal as Sam's."

"Oh, now you have to tell."

G chuckled. "For a first offense, my wards portkey the intruder to the La Brea Tar Pits. A first attempt against Sam's wards will get you portkeyed to ten feet above the ground somewhere in Zambia - minus a limb."

Nell stared at him in almost open-mouthed shock. "Good God."

"A second attempt on my wards, and you'll land somewhere near Mt. Aconcagua in the Andes - minus a limb. Second attempt on Sam's wards and third attempt on mine are lethal."

Nell shook her head. "And here I thought you were such nice, easy-going guys."

"We are," G agreed easily. "But if you try to invade our homes, all bets are off."