Why hallo thar. This is basically a shameless Jack whumping story. A couple of things I need to point out: The language I have Jack reference in this story was made up by me. I think it might exist in canon, but I'm not sure. Also, I'm aware that Hogwarts is very big and that it would probably take more than a week to explore every room. Just humor me. And now, I must bid you enjoy the story.

Disclaimer: Doctor Who doesn't belong to me. Neither does Torchwood.

Captain Jack Harkness trudged miserably through the muddy cesspool that at one time had been a dirt road. Ahead of him and through sheets of rain a medieval castle loomed in the darkness.

He was in Scotland, tracking down the highest concentration of energy in the area so he could record it on Torchwood's equipment and make it stop setting his sensors off. When Torchwood had first picked up the loud energy, right after a technology upgrade, Jack had thought the energy was of alien origin just like the rest of his team. It had taken him an embarrassingly long time to figure out that the energy signature was familiar to him not because he had run into a particular species of alien before, but because he had grown up down the street from a scientific research laboratory, which was the typical living space of the remnants of a then-ancient human society—witches and wizards. And since he was the only one with any knowledge of magic, Jack was the one stuck traveling to a magical school—Hogwarts or something like that, which was a completely disgusting name in Jack's opinion. At least Torchwood rolled off the tongue in a somewhat pleasant manner.

By the time he made it to the castle he was soaked to the bone and cursing the entire wizarding world. In the 51st century, wizards were top-of-the-line scientists with a kick. In the 21st, they were apparently idiots who had yet to figure out concrete or basic electricity.

Thoroughly irritated, he stomped through the front doors of the castle and into a large, empty meeting hall. He exited the hall and moved upward through the halls and staircases, searching for some sign of life. After a good long walk, he came upon a seemingly randomly placed gargoyle. It wasn't until he stopped to examine it that he realized that there was a person standing next to it in the shadows. It was a tall man with long black hair who scowled as soon as he was noticed.

"So," he drawled, "you're the muggle that's stumbled into our school. Follow me."

The man then turned haughtily, muttered something at the gargoyle, and swept up the staircase that had just appeared. And Jack, never one to back down from a challenge, put his hand on his gun and followed.

In the office above the gargoyle, Headmaster Albus Dumbledore let a stern expression settle on his face. He found it slightly disturbing that a muggle had been able to just walk into the castle like they owned it. Hogwarts had enough concealing and repelling charms to set an army of muggles marching in the opposite direction—or at least it was supposed to. As soon as he dealt with this muggle, he would take a walk around the castle and check the charms and wards.

He had a full minute to prepare his face before Snape led the muggle into the office. Dumbledore was made even warier by the way the muggle took in his surroundings—guarded expression, hand resting on what appeared to be a concealed weapon. The last thing they needed was a private military faction interested in the magical world.

The muggle didn't give Snape or Dumbledore time to talk, though. "Captain Jack Harkness, at your service." He reached towards Dumbledore, held his hand there for a long second, then withdrew it when it became apparent Dumbledore wasn't going to shake it. He pulled a plain black wallet out of his coat and held it up open so that Dumbledore could see a business card that proclaimed him head of Torchwood Three. "I'm with Torchwood, sir, and I need to check your school for alien presence and record its energy so it will stop setting off our sensors. It's very sensitive equipment, ya know?"

"Alien?" Dumbledore asked. "How exactly do you mean?"

"Well, to give you the short version, there is sentient life outside the Earth. Sometimes it ends up on the Earth, and it's Torchwood's job to send it back to where it belongs. At first we confused the energy from your school with energy that is commonly given off by alien technology. I need to record your specific energy patterns so our equipment won't sound alarms every time it gets picked up. And before you ask," he inserted hastily as Dumbledore opened his mouth, "I know perfectly well what the wizarding world is. I'm no muggle."

Dumbledore and Snape shared a swift look. "Well, Captain Harkness, I see no reason why we can't let you look around the school. If you would be so kind as to step outside for a moment so I can speak with Professor Snape privately?"

They waited for Jack to step out onto the stair landing then turned to each other. "What do you think, Severus? He claims he isn't a muggle, but that makes his appearance even more suspicious. Do you recognize him from your Death Eater meetings? A foreign correspondent, perhaps?"

Snape frowned. "I haven't seen him before. It is suspicious, though…I couldn't get into his mind, either."

"Well," sighed Dumbledore, "we have on our hands a man who acts and dresses like a muggle, carries muggle weaponry, and lives in the muggle world. Yet he claims he isn't a muggle, and apparently has wizard skills. So how do we know if we can trust him?"

The two of them were silent for a moment, all too aware of the fact that they were limited in time—their mystery man was waiting and keeping him out there too long would only make him suspicious.

"Headmaster," Snape said suddenly, "why not give him a little…test? Set a boggart on him—it's common fare for any person who has magical training or a magical background, but a muggle with just basic knowledge of the wizarding world wouldn't know how to react. It would be a simple test, and we could pass it off as an accident. After all, it's impossible to keep all the spare classrooms clean all the time…"

Dumbledore nodded thoughtfully. "It would give us an insight into his character, as well. It is a well-documented fact that boggarts often show you not only what you fear, but what you feel guilty about. Even if he does have wizard training, the shape of his boggart could give us a clue as to how trustworthy he is. Very good. I'll have you take him to look through the school tonight—I believe there is a boggart that needs taking care of in the old transfiguration lab room on the second floor. Take him there first."

Snape gave a sharp nod, then stepped out of the office. He was mildly impressed to find Captain Harkness leaning against the wall by the top step, a whole three feet away from the door. At least he hadn't been trying to listen in. "Come with me, then, and you can do your…recording."

Jack obediently fell into step behind the brooding professor. It was a little surprising that they were just going to let him do his thing in their school—normally he had to do more convincing than that—but he wasn't about to look a gift horse in the mouth. He trailed behind the silent man down five floors, at which point Snape spun around, forcing Jack to an abrupt halt.

"What exactly do you need to do?" the professor demanded brusquely.

Jack gave him a disarming smile. "Oh, just poke around in all the rooms of the castle, take some readings. We can start just wherever."

Snape nodded in seeming satisfaction. "Very well then. Follow me."

Jack followed him into what appeared to be an unused classroom. The desks were covered in dust and the only décor besides a teacher's desk and student desks was a dusty old wardrobe standing in a corner. Jack noted with curiosity that the wardrobe appeared to be faintly rattling.

"Do any creatures happen to run around this school? You know, magical animals or something that I should know about?" Jack inquired, slowing moving closer to the wardrobe.

"Sometimes magical beasts find their way into the school, yes. Nothing out of the ordinary for a place with such highly concentrated magic." Snape replied calmly, purposefully staying in the doorway of the room.

Jack edged a little closer to the wardrobe, hand on his gun again. So this was the catch—set the outsider against a magical monster. Well, he didn't care. He had been to the end of the universe and back, and if he had learned one thing it was that nothing was completely impervious to good old fashioned bullets. At the very least a couple of bullets would distract it long enough for Jack to get behind the cross man who had set him up for this.

Jack took one more step towards the wardrobe, and whipped his pistol out as the wardrobe door burst open—

Only to let it slowly drop as a horrifically familiar little boy stepped out. Early 20th century outfit, messy blond hair, gas mask…And a bloody slash across the back of one hand.

"No…" Jack breathed softly, taking a step back.

"Mummy?" the little boy inquired innocently. "Are you my mummy?" He reached out to Jack with his bloody hand. "Mummy, can't you see me? I'm right here."

Snape watched in shock as the previously confident Captain backed away from the boggart in horror. He had been prepared to see something bloody—it was common for Death Eaters to see their own bloody torture victims when faced with a boggart—but for some reason this childish apparition was worse.

"It's a boggart," he offered aloud, "it takes the shape of whatever you fear the most. The incantation riddikulus will repel it."

Jack's face had lost all color, and he had backed himself up against a desk. "R-riddikulus." he managed weakly. The boggart turned to smoke for a brief moment, and Jack was relieved—he never wanted to relive the experience of the empty child ever again—but then it became solid again, this time in the familiar guise of his original Doctor. Close-shaven hair, too-big ears, leather jacket, and a look of extreme disapproval on his face. In fact, he was wearing his "you've just screwed the universe over. great going, you bloody stupid ape" look. Jack turned his head away, unable to stand the angry glare.

"Riddikulus." he murmered again, and this time when the boggart reformed it was Rose. Beautiful Rose, with blood dripping down the side of her head and tears in her eyes. "Jack…" she choked out desperately, and Jack had to fight the urge to run to her. He knew it was an illusion—he hated the wizards for forcing him to bear this—he found a tear streaking down his face. "Riddikulus!" he choked out again, desperately.

It was the new Doctor.

He wasn't wearing his customary grin, though. Instead, he appeared to be masked behind his cold Time Lord exterior—head tilted up, severe frown on his face, arms crossed against his chest impatiently.

"Well, look who it is." the apparition sneered, looking down its nose at Jack. "The freak that just can't die." Jack vaguely recognized—and was grateful, considering he had an audience—that the pseudo-Doctor was speaking common trade language and not English. It made sense; Jack was more fluent in Common, so the TARDIS had always translated speech into it for him. "I abandoned you twice and you still didn't take the hint. I guess you're stupid as well as a freak of nature, aren't you?" the creature continued ruthlessly, and Jack decided he couldn't take this any longer. He turned and ran, past the confused-looking wizard in the doorway, down one last floor, and out the front doors.

NINE DAYS LATER

Jack sighed as he took the reading from yet another room inside Hogwarts. Despite his encounter with the boggart, Jack had stayed at Hogwarts, reasoning that he had to do what he had come to do or Torchwood would have even less peace than normal. He had been assigned a different "tour guide" and had begun the tedious task of looking through the castle for signs of alien energy. He hadn't found anything, so far, and he was pretty sure he had been through most of the castle.

"Well, sir, I think that'll be all. Do I need to show yeh back to the Headmaster?" the old caretaker who had been showing him around asked, bowing and scraping a little too much for Jack's comfort.

"No, that's fine. I can make it on my own." Actually, Jack intended to take care of one last piece of business before he went to thank the Headmaster for letting him do his job.

One thing that Jack believed in very strongly was facing his fears, and he intended to do just that. He was going to go back to the boggart room and take a final reading.

When he arrived, he was surprised to see Snape facing the wardrobe, apparently bracing himself to open it.

"Oi, Nutty Professor." Jack drawled, leaning against a desk.

Snape spun around, wand out. "Oh, it's you." he suddenly looked intensely awkward. "Er. I was just about to get rid of the boggart—you know, can't have one loose in the school with the children running about, sticking their noses where they don't belong."

Jack gave him a blindingly fake smile. "I suppose the spell you gave me to use was just a piece of nonsense, then."

To his surprise, Snape actually looked a little offended. "No, no. The incantation was right. I just—well, I might have left out—" the professor looked torn for a long second. "Fine. Look, the spell doesn't work unless the intent is right. You have to envision the form the boggart has taken as something humorous to yourself, or the incantation only forces the boggart to change into something else you fear. I'm…" he paused again, now obviously struggling with himself. "I'm…sorry, that I made you go through that. I don't—I suppose I don't have the best history myself, and I would be angry if someone did that to me…so…" Snape looked away, obviously embarrassed. Jack got the impression he didn't normally go around apologizing to people.

Jack pushed himself away from the desk and positioned himself in front of the wardrobe, gently pushing Snape away from it as he did so. "That's all right, then." he said calmly, once again eyeing the wardrobe warily. "It's my fault for not coming to terms with my past, after all."

The wardrobe opened up again, and again the little boy stepped out. Jack smiled.

"The thing is, Professor," Jack said quietly as he lowered himself to one knee to put himself at the child's height, "my life hasn't exactly been a barrel of laughs, and I suspect yours hasn't been either, but…" He smiled again, warmly, and gently murmered "riddikulus".

Instead of changing to mist or switching to something obviously humorous, a golden cloud surrounded the boggart for a moment, then lifted. At first it seemed like the apparition hadn't changed…But then the child stirred.

It reached up and pulled the mask off of its face, revealing a smiling five-year-old.

"…sometimes the story has a happy ending. And that's what's important, isn't it?"

And Snape thought it was.

END