Enjoy.

"You sure about this, Harry?" Harry was about to strike the door when he felt his girlfriend's hand slip into his. He was honestly surprised it took her this long to do it, he thought he'd be the one to crack first. In his opinion, Hermione was the one made of sterner stuff than him.

Seeing as how somebody was out for his blood, and one of Harry's friends and an innocent girl were caught in the crossfire, he knew they might have to adapt. So far, until they planned further, this involved he and Hermione downplaying their relationship. Whoever was watching needed to think Harry and 'Ginny' were together, or at least closer to being together.

Harry didn't like this arrangement, he much preferred to preach his feeling to the world for the brunette witch, but Hermione insisted this was for the best. Not that she was quiet about her own annoyance, though.

On one upside, being a Hogsmeade weekend, many students were out of the castle for the day. Less people for the rumor mill to work with and spread news about.

Speaking of Hogsmeade, Harry cursed the fact that the Marauders Map only covered Hogwarts itself and its grounds. He'd triple checked the damn thing already but he hadn't much hope for finding Ginny or Astoria that way. It would have been way too easy, and if there was something he'd learned in life, it was that Harry James Potter was rarely allowed easy.

As for Hogsmeade itself, it was a likely candidate. Close to Hogwarts, full of more than a few hidden corners and crevices you could hide someone, and nobody knew the denizens well enough to tell the difference between a new resident and an old one. If Harry was going to hide someone but keep them close to Hogwarts itself, the village of Hogsmeade would have been the top of his list.

Then again, what better place to hide someone in plain sight than Hogwarts proper? It wasn't exactly common knowledge that Harry had the map, so nobody would account for it, at least not intentionally. Now that he thought about it, what exactly would it take to hide someone from the map? Could it even be done? Peter Pettigrew certainly couldn't in his animagus form, but Harry rather doubted he knew the map was still in use.

"Nope." Harry pulled himself from his thoughts to answer his girlfriend. "But for now, it's all we got without going to someone higher in the faculty for help."

It was for that exact reason that Ron and 'Ginny' were not with them. Both were currently serving their detention sentence with McGonagall, and would continue to do so until their letter to Mrs. Weasley got a reply. While Harry had no doubt it would, they'd have to use the cover story of somebody trying to play a prank on the trio for now.

Harry couldn't help but feel bad for his best mate. Detention with their head of house wasn't so bad, especially since she herself was eager for evidence that her lions were not at fault, but the fact that he had to go to that detention with Daphne. For obvious reasons, the blonde couldn't very well go as herself. She had to take another dose of the polyjuice potion and impersonate their fellow Gryffindor again. Something that both her and Ron were deeply uncomfortable with, but couldn't do anything about.

"And if we're not careful doing that, there's no telling what could happen to Ginny and Astoria." Hermione sighed, her unease about the whole situation obvious for any and all to see.

"These." Harry held up the small paper wrapped stack of brownies. "Are still our only lead. If we're lucky, whatever's in them is something super rare that's hard to get or make."

"In what world are we that lucky?"

"Certainly not this one, but I did manage to catch the eye of the most amazing witch in the country so..."

"You don't have to flatter me." Hermione pointedly ignored the way her cheeks tinted pink. "You've already got me hook, line, and sinker."

"True." Harry shrugged, a warm smiling tugging at his lips while his thumb ran over the knuckles of Hermione's hand. "But I never get tired of that lovely smile of yours."

"Well, if you would like to see it more often, I suggest we get this mess sorted out and figure out how to deal with whoever is trying to kill you this time." Hermione went to knock on the door but stopped. "The fact that I even have to say something like that is just… ugh!"

"Unfair, I know." Harry nodded in agreement but they'd never get anything done or figured out just standing out in the hall like a couple of buffoons.

Forcing down any and all other thoughts, Harry rapped hard on the solid wood door.

There was a small commotion on the other side before a muffled voice from within told the couple they'd be right there.

A couple of minutes later, the door opened to reveal one Horace Slughorn.

"Ah, Harry, my boy, always a pleasure to see you." Slughorn's face lit up like it often did whenever Harry talked to him directly. "What brings you by my door on this fine day?"

While it most certainly was not a fine day, Harry knew the professor didn't need to know that little tidbit. Not yet, at least. As it was said, one battle at a time.

"Professor, we need your help." Harry made a show of looking up and down the hall, as if he was looking for eavesdroppers. Something he knew Slughorn wouldn't miss. Not like it was entirely false, anyway. "A favor, if you will."

If Slughorn's face lit up before, this was more akin to all the lights in Time's Square over in America plus every other light in the British Isles. After all, to a man like Slughorn, the F word was like a precious and sacred artifact. A favor from the boy-who-lived? Harry might as well have been offering him the literal Ark of the Covenant.

"Please, do come in." Slughorn wasn't jumping for joy, but Harry could see it was a close thing as the older man ushered the teens inside. Not before he gave the hallway a once over of his own. If Harry wanted secrecy as part of this favor, Slughorn would make sure the boy got it.

"Apologies for the short notice, professor, but we have need of your expertise." Hermione explained as she placed the offending deserts on the table. "No doubt you saw our little… altercation, in the great hall."

"Indeed, I did." Slughorn nodded forlornly, lips pressed into a thin line. "Wish I could say that was the first of such I've seen in my years teaching here, alas, such things are inevitable among young witches and wizards."

"Then you already understand our current predicament." Harry called their teacher's attention to the brownies on the table. "When these suddenly showed up, sender unknown, we instantly got real suspicious."

"Perhaps…"

Rather than verbally interrupt their professor, Hermione merely raised a hand as if she was in class to stop him. "We had the same thought and checked it out, we can say with absolute certainty these did not come from the Weasleys."

"Hmm… so you wish me to test for any love potion?" Slughorn was half right, at least. Most other teachers would be making a comment about why they didn't go to their head of house, but Slughorn wouldn't call attention to that.

"Actually." Harry was the one who explained. "We would like you to, yes, but to also test for anything else, too. Hermione got a real bad feeling about them and she's rarely wrong. And we'd like whatever you find to be discreet."

"Certainly." Slughorn cheerily agreed. Again, not mentioning the fact that keeping secrets like that had to be against a number of Hogwarts rules for their teachers. But this was a chance Slughorn would never allow to pass him by, a fact Harry had been counting on. "After all, if someone was trying to poison you, and you didn't know who, it wouldn't do to have that fact shouted from the rooftops."

"That's what I said." Harry winked at his girlfriend. It had actually been Hermione to say that, but Harry continued feeding Slughorn's ego to make their job smoother. "We'll have an easier time turning the trap on the trapper if they don't know we're onto them."

"I must admit, that is cunning worthy of any Slytherin. Ah, such a loss for my house." Slughorn shook his head in what could have been either genuine sorrow, or quite good acting.

Harry almost laughed. He couldn't help but wonder if Slughorn knew how obvious he was being. If Harry had been a Slytherin, with Slughorn being his head of house, well… Christmas coming early wouldn't even begin to describe it. If only the professor knew how close Harry had come to being sorted into Slytherin.

"Uh, professor?" Hermione struggled to keep the annoyance out of her tone. "Your testing?"

"Ah, yes, quite right, Miss Granger." Slughorn shook himself from his revere and drew his wand. He made a brief motion with it before holding it over the treat's surface. It was only the confused look on his face that clued Harry into the fact that something was wrong.

Rather than ask what it was, Harry decided to wait and see what their teacher did. Hermione was about to do just the opposite, but a poke of her side with his finger caught her attention. When Harry shook his head at her, she got the message.

"Odd…" Slughorn mumbled under his breath before trying his spell again.

When it failed again, the potions professor scowled slightly, a strange look on his ever-cheery features.

Without another word, Slughorn walked away. Harry was about to ask where he was going when the man reappeared with a small cauldron. Plopping the container down on the table, he disappeared again only to reappear with what Harry could only assume were potion reagents.

It occurred to Harry that he'd never seen Slughorn genuinely at work. While he taught their class, he always focused on instruction and actually teaching, this was almost like a while different side to the man. In fact, Harry wondered if he could tell he and Hermione were still standing here.

One thing Harry did find funny was that look of absolute focus on Slughorn's face. It was eerily similar to Hermione's when she read a particular book she'd become engrossed in, but Harry didn't think for a second she'd find the comparison as humorous.

Knowing full well Slughorn would share whatever he found, Harry kept his mouth shut and watched a potion master in his element.

Heating his mixture and mixing his ingredients, Slughorn waited until the temperature was to his liking. Once it was, he took a chunk of a brownie and crunched it up before dumping it into the cauldron. Breaking another piece off, he tossed that one wholesale, but gently, into the bubbling liquid.

After that, Slughorn simply watched and waited.

Peering over, but making sure to stay out of the professor's workspace, Harry couldn't tell what the man was looking for. All he saw in the cauldron was a number of assorted colors with random bubbles. Whatever it was Slughorn was searching for, Harry knew it was something only he'd be able to see.

"Harry…" Harry almost had to do a doubletake at the sound of Slughorn's voice. Gone was the joviality, the good humor, and friendliness. In its place was genuine worry and what might have actually been fear. "Where did these come from?"

"We don't kn…" Hermione attempted to answer but the look Slughorn gave her at her withering on the spot.

"You're sure?" Slughorn turned to face Harry and actually gripped the boy's shoulders and gently shook him. "You're absolutely sure?"

"Definitely." Harry mentally shook off Slughorn getting physical, the fact that he was even doing so in the first place meant this had to be serious. "They just showed up one day with no markings. At the time I thought they were a present from Hermione."

Slughorn's head whipped toward the brunette so fast, both teens feared for their professor's neck.

"They didn't come from me!" Hermione was quick to meekly answer. "We asked around but nobody seems to know, either. That, and what happened with Ron and Ginny, had us to worried."

"We also checked with a number of people, too. Ron and Ginny all had an alibi and couldn't have placed them, either." While they hadn't lied about knowing the Weasley's were not involved, Harry now did have to lie to exonerate their friends.

"Somebody is definitely trying to harm you." Slughorn took a steadying breath before motioning to the brownies. "Is there anymore of these?"

"A few, we have someone trustworthy keeping hold of hold of them so nobody touches them." Harry had taken Daphne's advice about not putting all their cards on the table when they went to Slughorn. It was still possible he was involved, and just in case, they'd better not bring all the evidence right to his literal door. Which is exactly why Neville, something Harry had no intention of telling Slughorn, was trusted with most of the potentially dangerous food, and a second but smaller portion was hidden somewhere only Luna knew.

"Do they know…"

"That they might be poisoned?" Harry didn't have the hang up about interrupting a professor that Hermione did. Ignoring his girlfriend's scandalized look, he continued. "Yes, we felt it wouldn't be a good idea to bring a whole platter here."

"Good thinking." Slughorn nodded, his face ashen. "But I must recommend you destroy these and any others you have immediately."

"Professor." Hermione hesitated, almost afraid of what the answer to her question might be. "What is in these things?"

"Manticore venom." Slughorn visibly shuddered at the words.

"Isn't that fatal?" Hermione paled, her kneejerk reaction to reach out and grasp hold of Harry's arm.

"It depends." Slughorn admitted. "If directly from the manticore's stinger? Totally. Smaller amounts? Depending on how small, it's a nasty paralytic. But even then… would you like to no the gory details?"

"No." Hermione gripped Harry's arm so tightly, she was starting to cut off his circulation. Not that Harry would complain about his girlfriend's touch. "But I think we need to know."

"Best case scenario…" Slughorn cleared his throat. "You ingest one of these, and are paralyzed for hours while portions of your organs shut down. If healthy enough and help reached you in time, you might recover from that. But you would never be the same. It would be quite similar to the aftermath of a severe stroke."

If help reached you soon enough. Harry mused on those words. Part of Daphne's orders were to get Harry alone before giving him the tainted food. That certainly explained why.

"And… "Hermione swallowed past the lump in her throat and forced her next words out. "Worst case?"

"Most of the first. Paralysis, organ failure as a start."

"Start?"

"It would depend on how potent the venom still is." Slughorn paused, thinking over his next words. "My tests only determined the presence of the venom, not the potency. At its most potent, as in directly from the stinger, death is instant. But depending on how much was used in baking these and how long since it's extraction, its outcome would be different."

"Different, how?" Harry had a bad feeling he wasn't going to like this next part, not like he'd liked the rest of the lecture.

"At it's most potent using this process," Slughorn motioned to the brownies, "it will not be fatal right off the cup, but it will still be enough to kill you. Your body will be paralyzed while your organs cease functioning, just like I said, but the worst come after that. As the venom spreads, your internal organs will begin to liquify and melt, while you feel every excruciating moment. All the while unable to move or even speak."

It didn't really match Daphne's description of what the poison was, but she did admit to having no clue what the poison was. She could have easily just been guessing.

With each word, Harry could see Hermione growing paler as the reality of the curse they'd dodged set in. Harry wasn't the only one about to eat those brownies before Ron stopped them. By the time Slughorn stopped talking, Hermione looked on the verge of fainting. Something Harry never imagined in a million years seeing from his girlfriend. Fainting? Hell no, but she might…

Harry had seen Hermione's next act coming miles away and was already following beside her to the nearby rubbish bit. He'd taken hold of her bushy locks seconds before the vomiting started.

"It would continue until the venom reached your heart." Slughorn finished the impromptu lesson in death by manticore venom with a wince. "Many witches and wizards have that reaction after hearing that."

"So, I take it this is something not every bloke on the street can get their hands on?" Harry continued to hold his girlfriend's hair from her face with one hand while rubbing soothing circles into her upper back with the other, all the while trying to ignore the sounds coming from the most important person in his life.

"No." Slughorn shook his head. "While the substance is not outlawed, it does serve a number of other purposes, after all, it is not easy to come by. I don't even have any in my personal stockpile."

"Is there…" Hermione weakly croaked from where she remained hunched over. "Any antidote?"

"That is the one bit of good news." Slughorn's cheery disposition returned, though it was a bit forced. "Unlike the basilisk, there is, indeed."

"Professor…" Harry thought about it and decided he'd try to leverage that favor for a little more. "Do you happen to have any?"

As I'm pretty sure I've stated before, Half-Blood Prince is the one Harry Potter work I've seen neither movie nor read the book, which is why Slughorn's character is based only on clips and trailers I've seen. I can only hope I got it close enough to right.