Author's note. Just to be clear, I love the characters of Snape, Remus and Sirius but I do think they all have flaws. Snape's are obvious but Remus's and Sirius's are a little more hidden. This one shot explores one of the little know but dangerous flaws that Remus has.

Enjoy and please.

Harry walked forlornly along the corridor, his mind dwelling on the fact his favourite and by far the best Defence teacher was leaving the school. Professor Lupin had been forced to resign rather than wait for the storm of outrage and complaints which would be coming in the next few days and would have forced Professor Dumbledore to sack him. He had wanted to retain his dignity and leave the school with his head held high and Harry knew that everyone was going to miss him.

"Well, all but one," the young boy thought savagely.

Thanks to a certain Potion's Master, the entire school knew Professor's Lupin's secret, that he was a werewolf. And now everyone, especially the Slytherins who had hated Professor Lupin on principle, would be owling their parents with the news. And of course, the parents would only see the monster, the danger to their children and would be demanding his resignation. At least Professor Lupin didn't have to wait for that to happen, he could get away safely.

Harry felt his fists clench, it just wasn't fair. Professor Lupin had been beyond brilliant, not only had he actually taught them something in DADA class but he had made it fun. And while Harry generally enjoyed school, he wasn't on fire to attend most of his classes but Professor Lupin made you really want to go to them. But now, they weren't going to have any more fun lessons, they would probably end up getting another terrible teacher for the subject.

The young Gryffindor wished he could do something to change this but it was impossible. Even turning back time wouldn't change anything although he dearly wished that it could. The more Harry thought about it, the angrier and more indignant he became. What right had Snape to blab Professor's Lupin's secret to the world? If Snape had only listened for five damn minutes, then Pettigrew wouldn't have gotten away and Sirius would be free. Professor Lupin wouldn't have ended up transforming and wouldn't have felt so responsible for putting his students in danger that he resigned.

In fact, Harry was so angry, that he started marching straight in the direction of the dungeons. He fully intended to give Snape a piece of his mind, even if it meant detention for cheek. He knew after Sirius's escape, Snape was just looking for an excuse to punish him, well; he would happily give him one.

"Enter," came Snape cold voice once Harry had reached his office and knocked smartly on the door.

Taking a deep breath, Harry opened the door and entered.

Snape was at his desk, he appeared to be going over papers, his black eyes were certainly fixed on them. As Harry stepped into the room, Snape's eyes lifted and narrowed as they found who had just entered. He didn't speak however, just continued on with the piece of parchment he was currently marking. Harry stood there stiffly, waiting for Snape to acknowledge him.

At long last, Snape put aside the paper and straightened, pressing his fingers together and looking at Harry.

"What do you want, Potter?"

"I want to know sir," Harry began, barely keeping a civil tone. "Why you told the Slytherins about Professor Lupin?"

Snape raised an eyebrow.

"Is that all?" he asked in his cold tone. "I thought it might be something important."

"This is important," Harry burst. "Thanks to you...sir, we've lost the best Defence Against the Dark Arts teacher we've ever had."

"He is hardly the best," Snape said dismissively. "I could name at least five better teachers during my time here."

"He's loads better than Quirrel and Lockhart," Harry shot back which made Snape smirk.

"Potter, everyone is better than those two. I taught you more in one day than those two did over two years."

"Professor Lupin didn't deserve to be fired," Harry retorted hotly. "This is probably the first job he's had in ages and you ruined it for him."

"I beg to differ Potter," Snape said silkily, apparently answering only Harry's first point. "Lupin deserved everything he got, frankly, he deserved more."

"Why?" Harry demanded. "Why do you hate him so much?"

"You mean apart from the fact that he almost killed me?" Snape sneered as Harry said.

"Professor Lupin didn't have a part of that, I know he didn't."

"He might not have directly taken part in that scheme but he was a part of it," Snape said bitterly. "He huffed for perhaps a month about it and then he was right back with his friends, Potter and Black. He didn't care that Black had deliberately and maliciously used him for some pathetic, petty revenge. Lupin simply excused it and forever stood aside and continued to excuse any atrocities they committed."

"What atrocities?" Harry asked in confusion.

"I won't go into the sordid details," Snape said cruelly. "But let's just say Potter, there's a reason so many people were ready to think the worst of Black after the Dark Lord's fall. That willow incident may have been his worst action at school but many of his other actions and motivations were highly questionable. Do you find hanging Slytherin First years upside down from the Astronomy tower, funny Potter?"

"Of course not," Harry shocked. "They...they didn't do that, did they?"

"Why don't you ask Professor McGonagall if you don't believe me," Snape said with a malicious smirk. "She was the one who assigned them detention after all."

Harry stared at Snape, shaken by the revelation but not put off entirely.

"What does that have to do with Professor Lupin?" he asked after a moment.

"Merely that he proved he can never be a real teacher," Snape said with a light shrug. "And therefore, does not deserve to remain at Hogwarts."

As Harry stared at him, confused, Snape said.

"Potter, assume for the moment, that Black really was after you..."

"Wait a moment," Harry exclaimed in surprise. "You know he's innocent?"

"...Yes," Snape bit out, looking exceedingly annoyed and disappointed about this fact. "Professor Dumbledore explained to me what happened."

"Why didn't you listen to us?" Harry demanded his anger back. "All we wanted was to hear their story, nothing more but you were all for dragging them to the bloody Dementors."

"Do not speak to me in that tone," Snape abolished sternly. "And I suppose that could have gone better..."

"Yeah, we might have actually brought in Pettigrew," Harry sneered bitterly, still sore over his lost chance at a real family.

"One more cheeky remark out of you Potter and it will be detention," Snape warned in a deadly tone. "And perhaps Pettigrew would have been brought to justice but the fault is not entirely mine. If that wolf had even thought to revive me, things could have been different."

"I'm sure you'd have been a great help, sir," Harry said, in a sarcastically polite voice.

Snape offered him a tight sneer before saying.

"As I was saying before Potter, imagine for a moment that mutt Black was guilty..."

"Sir?" Harry said, still bemused by this.

"You did not know he was a dog, did you?" Snape said and Harry shook his head, feeling even more confused.

"So, if an pathetic looking mutt had sidled up to you near the Forbidden Forest, looking mournful and in need of comfort, you'd have probably have gone to it," Snape continued.

"Um...maybe," Harry said he really wasn't sure. All year, he'd wondered if a Grim was after him, he didn't know if he would have gone near Sirius in dog form.

"Imagine how easy it would have been for him to have snatch you up and made off with you into the Forest, to do what he wanted," Snape said cruelly as Harry stared at him. "If Black had been guilty, he could have easily done something like that."

"Yeah," Harry admitted. "But he wasn't after me."

"But you didn't know that?" Snape asked and as Harry shook his head, added. "I did not know that, Professor Dumbledore did not know that, your little friends did not know that and...Lupin did not know that."

"No...he didn't," Harry said softly.

"But Lupin did know Black's little secret," Snape continued.

"Yes," Harry said slowly.

"And yet," Snape stated. "Despite the fact he knew Black's ability, one that no one else bar Pettigrew knew of, even knowing that Black could use this ability to kidnap or kill you, he said...nothing."

Harry frowned, he'd never thought of it this way. Snape continued.

"Twice, Black entered the castle and on the second occasion, he made it as far as your dormitory room. He was barely a foot away from your little sidekick, with a knife. Who knows how many other opportunities he had to cause you harm and yet Lupin remained silent."

"He...he didn't want to disappoint Professor Dumbledore," Harry said rather weakly.

Snape gave him a scathing look.

"We both know that while Professor Dumbledore might have been mildly disappointed for their selfish foolishness, he would also have been impressed by their daring cleverness."

Snape said this last bit with a pronounced sneer.

"He would have forgiven Lupin because with that crucial information, we could have protected you all better. We could have ensured that Black never even made it to the castle steps."

"Never mind," Snape said as Harry opened his mouth. "That he actually was innocent, we all believed him to be guilty. And yet Lupin considered a murderer more important than yours and the students' life."

"He didn't...," Harry began but Snape overrode him.

"Then why didn't he tell? He believed that Black had sold his soul to the Dark Lord, had betrayed the whole Potter family and killed his own friend in cold blood. Black was successfully evading all of us, it was only a matter of time until he had a shot at you...and still Lupin said nothing. His loyalty to Black was more important than your very life."

"I...," Harry began, although he had no idea what he was actually going to say.

"The interesting thing about werewolves," Snape suddenly said, smirking at how deflated Harry was. "Is that like ordinary wolves, they possess a pack mentality. Virtually all werewolves live in werewolf packs, with a dominant alpha and beta wolf. The other wolves are submissive to this pair and will follow them no matter what. Lupin happens to be of the submissive strain and this explains much of his behaviour. For him, the Marauders were his pack and thus, he followed them devotedly and blindly."

Harry could only stare at Snape, he couldn't even form a single word. Snape continued.

"I would say that James Potter was the dominant with Black as his beta. No matter how close either of them came to becoming Dark, Lupin followed them. Now Pettigrew, he was a fellow submissive, an even lower submissive than Lupin himself. That is why Lupin had no problem cutting him off when Pettigrew was discovered, why he so easily forgave Black. He was happy a dominant was back in power."

"It can't...," Harry tried but it was no good, Snape was carrying on.

"It is Potter. Lupin's loyalty to his pack is more than his loyalty to Dumbledore or anyone else, including you."

Sneering, Snape added.

"While you are the cub of the alpha, that alpha is also dead and Lupin never got a chance to properly imprint himself on you. Therefore, he does not consider you part of his pack and therefore, you do not have his ultimate loyalty. Only Black has that honour and that's how it shall always be unless," Snape said with a dark chuckle. "That wolf actually finds himself a mate, then perhaps she will earn equal status with Black. But that is the way of things."

"I...I still don't understand sir," Harry said softly.

Snape actually sighed and said.

"Potter, I and along with all the other teachers here, with the obvious exception of Professor Binns, would die for you."

As Harry balanced, Snape continued.

"And all the other students here at Hogwarts, we would fight to protect you all and do whatever it took to ensure you were all safe. Lupin proved this year that he could not do that; he would put his pack loyalty before yours and everyone else's safety. Not even when a student was almost murdered did he say a word. He cannot be trusted to put his duty as a teacher above all other duties."

Now Snape looked Harry squarely in the eye and said.

"That is why I destroyed him...before he destroyed you Potter. He was s caught up in the past that he forgot the most important part of his job here, taking that damn potion. One slip, that's all it takes for him to turn those he is meant to protect into monsters. He came far too close that night and if it wasn't for Black's intervention, you would have been turned."

Harry stood there, utterly defeated; there was nothing he could say to Snape's words. But Snape's next words surprised him.

"I suppose Lupid did perform one useful service, teaching you to perform the Patronus Charm."

"Uh," Harry said with a slight flush, realising that Snape must know he cast that Patronus that got rid of all the Dementors.

"I can hardly believed that a student like you could produce such a powerful Patronus," Snape said slowly, considering Harry.

Harry shrugged.

"If it makes you feel better sir, I knew I could do it because I'd already done it," he said, repeating the words he'd said to Hermione.

"Marginally," Snape said with a smirk. "You saved all of our souls that night."

Harry was squirming now, being complimented by Snape was just too much.

"I didn't mean to," he said at last. "I went there to see who had done it; I thought...I thought it was my dad. I saw someone casting the Patronus but I never thought..."

"That it was you?" Snape finished for him. "I suppose for once, your dunderheadness is understandable considering your unfortunate resemblance to that man."

"But it was him, in a way," Harry said quietly, hardly able to believe he was saying this. "My Patronus is his stag form and I only found that out an hour ago. He helped save us."

Snape grimaced, he clearly wasn't keen on this idea.

"In an extremely roundabout way, he did," he said coolly."Well, Potter, does that answer your question?"

"Yes sir," Harry said sadly, hating to believe him but Snape's logic had swept him away. Professor Lupin was still the best teacher he'd ever had and he was glad he hadn't told Sirius's secret but...logically, Lupin shouldn't have done that. He really hadn't known that Sirius was innocent and yet he had protected him, even if he'd done so by remaining silent.

"Do not fret Potter," Snape said dismissively. "You are Black's priority; Lupin shall not do anything else to put you in danger. He shall follow his alpha's desire although do not expect him to keep in touch. Owls are expensive if you don't work."

Harry frowned, he hadn't thought about Lupin keeping in touch but he wished he could. But Snape was right, he didn't want Lupin wasting precious Galleons on writing letters when he could be eating or paying bills.

"I'm sorry for disturbing you, sir," Harry said at last. "Have a nice holiday."

Snape made a motion with his hand, dismissing his student and Harry happily went. All that had just transpired, it was just too much for him. Snape complimenting him, telling him he'd die for him, explaining Professor Lupin's motivations...that would keep him occupied for a very long time. Probably just as well, considering where he was going for the summer.

After Harry had gone, Snape sat considering the closed door. With a sigh, he brought out his wand and waved it, murmuring an incantation. A pretty little doe danced from the end of his wand, cantering about the room before giving him a curious look.

"We can't chose our Patronus's," Snape muttered to himself. "They chose us."

The end

Author's note. Hope you all enjoyed that, it's something a bit different. Don't forget to tell me what you think.