Harry rolled up his sleeves as he waited for a response from the other side of the door. He had knocked twice now, and a large part of him wondered what was keeping the Potions Master from his favorite pastime of pushing Harry's buttons. The rest of him only wished that Snape would send him away so he could go back to the dorms and wallow in depressed agitation, as he had been for the majority of the last few days. Hermione had been particularly smug when she'd told him that he was to serve a detention with Snape for missing his classes all day. Apparently, the man thought "illness" wasn't reason enough to miss class. Never mind that the illness was faked, it was the principle of the matter; but at least Harry wouldn't have to fake actually being sick, since Snape obviously already knew, or would know upon seeing him, that he wasn't.

After several long seconds passed, the Seventh Year began to debate knocking a third time. He couldn't just leave; if Snape was testing him then he'd just wind up losing House Points and serving the detention anyway. He'd wait all night in this bloody corridor if the man made him, if it guaranteed he could spend the weekend comfortably curled into a ball between his bed sheets. Just as he'd made the decision to knock again, the door swung open to reveal the very subject of these thoughts after his knuckles connected only once with the wood.

"Sir, I'm here to serve my detention," Harry said solemnly, returning his hand to his side.

Snape sneered down his long nose at Harry. "You're late, you were supposed to be here five minutes ago."

Harry, knowing he'd been knocking for barely less than ten minutes, declined to comment. It would do little good to argue, it would only land him in another detention. Besides, Snape obviously knew he wasn't late, or he'd have taken house points as soon as he opened the door. Instead, he walked silently past the Potions Master into the empty classroom. He immediately looked for dirty cauldrons, but was surprised to find none.

"Not here, Potter," Snape said.

Harry assumed the man was referring to where his detention was to be served and followed him through an opening in the back wall, near the blackboard, that he'd never seen before. When he saw where it led, he had to wonder if any more than a handful of students in the Potions Master's time as a teacher knew there was a door there. He was standing in what could only be the professor's private lab. Part of him was amazed that he was being allowed in the room at all, the rest of him wondered why the man's private storeroom wasn't under such tight security as this was.

"You'll be cleaning the cauldron's I've accumulated, off to the side," Snape explained. "Do not use magic, as I've been using volatile ingredients that may very well explode if not cleaned out using the neutralizing cleaning agent you'll find nearby. You may fill the bucket at the sink whenever you feel you need fresh water, but move nowhere else than between those two areas with as direct a path as possible. I don't need your bumbling feet jeopardizing the potions I'll be working on."

Again, Harry held his tongue, knowing that even asking what the Potions Master was working on might land him in another detention. He took a cursory glance around, noting the location of the sink, before moving to the three size 12 cauldrons on the far side of the room. There, he found the bottle of cleaning solution, a scrub brush, and a wooden bucket for water.

"Can I mix the solution with water so I don't use as much, or would diluting it cause more harm than good?" He asked quietly.

Snape gave him an odd look from the doorway. "You may combine it with water, if you feel that would be easier."

Harry gave a curt nod as the man moved towards the gurgling potions at the opposite end of the long work table, and knelt to pour some of the solution into the bucket. When he'd dumped a few good splashes into the bucket, he walked over to the sink and filled it the rest of the way. Taking the bucket back to the work bench, he very carefully tipped the first of the three cauldrons onto its side, and began washing what had then become the bottom.

Several minutes passed before the Potions Master apparently grew tired of the silence, broken only by the sound of scrubbing and the gentle bubbling of his potion. "Miss Granger is concerned about you, Potter."

Harry leaned out of the cauldron he'd crawled into and looked at the man curiously. After a second, he gave a tired sigh. "I sort of figured, since I'm not in your class but am still serving a detention with you. This wasn't actually supposed to be a detention, was it?"

Snape didn't look up from his work. "Granger approached me following her class. She pleaded with me to speak to you, seemed to think I might be able to reach you where others had failed," The Potions Master said nonchalantly. "I agreed, on the condition that you come to me of your own freewill. I am surprised and somewhat heartened that she manipulated you into coming to me on your own by telling you that you were to serve a detention with me. It is vaguely-"

"Slytherin?" Harry supplied with a slight smirk.

Snape sent him a sharp look. "Enlightened would have been my word of choice. So, that I might avoid your friend's pleading in the future, would you like to talk about what has been bothering you? Or shall I assign you further detentions for skipping your classes all day?"

Harry frowned, sitting back on his heels. He knew Snape was serious, and he had no doubt he'd wind up having detention every night until graduation if he didn't at least pretend to cooperate. "It's complicated, sir. I doubt you'd really be able to understand." He paused for a moment, returning to his task. After several long seconds, he leaned back out of the cauldron to sit back on his heels again. "How did you become a teacher?" If looks could have killed, Harry would've been a smear on the floor. He realized too late what memories that question might bring about for Snape. "I-I don't mean…I mean the actual process of becoming a teacher, like paperwork, schooling, the specific NEWTs you have to pass, stuff like that. Sorry, sir, I should have been more clear."

The Potions Master sneered at him. "Indeed. Whilst I highly doubt your apparent confusion as to how to pursue a career in teaching is what has left you, as Miss Granger put it, 'down trod', I will assume this is all I am to get from you at this time?" Harry gave Snape the Potions Master's own trademark raised eyebrow, as if asking if he was really thick enough to believe otherwise. "Of course," Snape said, saying with a look just how much a waste of time this all seemed to him. "Why should you trust me? I've only saved your life countless times."

"And made me a laughing stock and verbal punching bag for every moment in-between," Harry pointed out unabashedly.

Snape raised an eyebrow, looking impressed, as Harry returned to his scrubbing. "Touché, Potter. Very well, you wish to know the process of becoming a teacher then by all means, allow me to oblige you." He cleared his throat lightly before he began, never once faltering in his tending to the potion before him. "Whilst not a particularly arduous pursuit, it does require time and a certain level of dedication, particularly during the testing phase. My circumstances allowed me to be fast-tracked through the program, and I have no doubt the Headmaster will see fit to do the same for you, should you tell him you that wish to teach at this school. Your NEWTs are only important insofar as determining what you may teach, and as far as I'm aware have no bearing as to where you may teach. So long as you receive above average marks in your chosen subject, you would be welcomed at most schools. However, following your graduation from Hogwarts, you would then need to proceed to university to pursue the appropriate advanced lessons in your subject. This is where you would find the Headmaster's help most useful, as he can see to it that you need not pursue the university courses, and could be tested on the knowledge you have already accumulated on your own, should he think it sufficient enough. If you were to agree to teach at Hogwarts for whatever time frame Professor Dumbledore asks, then you need not even pursue the certificate of teaching that would follow. An example of this would be Professor Binns." The Potions Master explained.

Harry backed out of the cauldron yet again, looking aghast at the older wizard. "Do you mean to say that Professor Binns' unfinished business on this plane is that he agreed to teach for a certain period of time and he hasn't exceeded it yet?"

"Yes, Potter, that is precisely what I mean," Snape replied, adding some powder or other to his potion. "However, the contract became null upon his death; he simply refuses to leave until such time as the agreement has been fulfilled. Were he to be fired, he could pass on, but the Headmaster feels he is doing an adequate job, and thus sees no problem in allowing him to carry out his dying request."

The Wizarding Savior scoffed lightly and crawled back into the cauldron he'd nearly finished cleaning. "The man's barmy if he thinks that Binns is adequate at teaching history. I get more information from the book than I do from him." He muttered under his breath.

"Quite," Snape answered. Harry started at being overheard, nearly banging his head on the cauldron, but Snape seemed to ignore his disrespect. "In any case, you could do as I and others before me have done and, upon being hired, acquire your certificate of teaching during the summer holidays. This is another means of nullifying any agreement of employment made with the Headmaster."

This statement gave Harry pause, and he pulled out of the cauldron entirely, standing up. "Do you mean to say…You're not here because you have to be? You're not staying at Hogwarts out of some obligation?"

Snape seemed to realize they were getting to the core of Harry's problem, and looked away from his potion. "Not at all, Potter. I am here entirely out of an obligation, only not to the Headmaster." Harry stared at the man in confusion. "I have an obligation to my students, Potter. I am not merely a professor, but a Potions Master. With that title comes a certain duty to the Wizarding World as a whole. Most Master's only fulfill that duty by working endlessly on experiments, some useful and some frivolous. I, however, have grown in time to believe that a Master of any subject owes each newer generation the benefits of their knowledge. Many with the same idea merely publish texts, or articles in magazines, whereas I have found in my students a means of relaying the true beauty of my work. But it is not only this that obligates me to continue teaching, it is also the glimmer in the eyes of my students when they come to understand a difficult problem, and the thrill of knowing that I have forever influenced my student's lives, no matter how small an influence they think I've made. I may never be seen as a good man, but I pride myself in the knowledge that I am a good teacher."

Harry was, needless to say, stunned by this revelation. "That's…I had no idea, sir, that teaching could mean so much…to anyone."

"Potter, what was it that you believed teacher's did, exactly?" Snape said, now seeming slightly agitated.

"I-I dunno, really," Harry stammered, feeling embarrassed. "I suppose I always thought teacher's taught only as a means of making sure each new generation was informed enough to function appropriately in society. But the way you talk about it, it sounds almost like an art, the way potions are an art. When I asked Professor McGonagall about becoming a teacher, she only told me that teaching was a strain, and that perhaps one student out of every thousand almost makes teaching worth it by actually making an effort. She sort of made it sound like a chore, a task that needs doing which only a few are willing to attend."

"I see," The Potions Master murmured distastefully, stepping away from his potion entirely after casting the spell that would put it in stasis. He turned to face Harry full-on, crossing his arms over his chest. "Potter, you will find many people, even teachers, who believe that, while teaching is useful, it is not as useful as many other professions. These people are wrong. If you expect to pursue teaching, you need to understand this. As teacher's, my colleagues and I serve a greater, nobler purpose than the mere transference of knowledge. We mold the next generation, in many cases more than their own parents or guardians do. In a school such as this, where the students remain for the majority of the year, they are exposed to us and our ways of thinking more than any other adults. Because of this we have a great influence on their perceptions, and on who they will become when they leave. Even in schools where the children return home each night, teachers have access to them for the majority of the day. We do not merely teach you subjects, we help you solve your problems, we teach you how to behave out in society. Why do you think the students here at Hogwarts are separated into different Houses?"

"Because it's where we'll learn best," Harry said without hesitation. Hermione had told him this hundreds of times.

Snape shook his head. "Why would you think that? Every student in every house starts with the same courses, and in Third Year every student in each house is given the same options for extra courses. Even in Fifth Year, it is your grades, and not your House, that determines which classes you can continue to pursue. So why would your House determine how or what you learned in your tenure here?"

Harry started to answer that his peers affected his learning, but realized that was wrong. They'd only affected him in his knowledge of the workings of the Wizarding World, and only because he'd been too embarrassed to ask his teachers. "I guess that it's my Head of House that has most of the influence. If I have a problem, I go to her; if I need help with my schoolwork, I'd guess she'd be the first person to speak to, even though I don't think any Gryffindor's brave enough to attempt that. Even if I'm in trouble, or need guidance, Professor McGonagall's the person I'm supposed to see."

"Precisely," Snape said, giving him a short nod of acknowledgement. "And, because of your House, she would give you advice best fitted to Gryffindor's qualities. If you were in Hufflepuff, then you'd be advised in a way that best suited the Hufflepuff qualities and the same holds true for Slytherin and Ravenclaw. You see, Potter, as teacher's we do not merely pass along knowledge, we also give you, our students, answers to questions that will affect your life and how you live it. Do you understand?"

"Yeah, I do," Harry said, giving a soft, breathy chuckle. "But, that's only made my problem worse."

Snape raised an eyebrow. "How is that?" He gestured to a stool at the bench, and took a seat on the one beside it.

The Wizarding Savior moved over and sat heavily. "I mentioned that I'd asked McGonagall about teaching?" The professor gave a curt nod, forgiving or ignoring his slip of the woman's title. "Well, I've been feeling absolutely rotten ever since I spoke with her, because all I've wanted to do since the DA in Fifth Year is teach, and she made it sound like a waste of time. I mean, yeah, I wanted to be an Auror so I could defeat the Dark Lord, but underneath that all I really wanted to do was teach, to give something back to the world…something that the world didn't already think I owed them, anyway. After my talk with her, I began to wonder if becoming a teacher would make that kind of a difference, and started wondering what else I could do. I've been sort of wallowing ever since then, because I don't honestly know what I'd do if it turned out teaching really was little more than a waste of time, like she said."

"So how has our discussion made this issue worse, Potter?" The former spy asked, looking somewhat confused.

Harry swiped his fringe down as he considered how to put his problem into words. "What if I can't handle it, sir? What if, in the end, I'm not good enough for such noble work and I wind up jaded and wondering what the hell I've done with my life, like McGonagall?"

Again Snape seemed to ignore his failure to use the Transfiguration professor's title, as well as his language. "If you truly wish to pursue this course, Potter, then I will go with you tomorrow to speak with the Headmaster, and together we will see what can be done to help you resolve these doubts, as it is apparent you will get no assistance from your own Head of House." He said with finality. "Additionally, you will come to my office once a week to discuss other options, should your doubts prove too overwhelming. I am well aware that asking students to choose their career paths in a five minute meeting in their Fifth Year is sometimes asking too much, and together we may be able to glean what other careers might suit you best by digging further into what each one entails."

The offer thinly veiled as a command struck Harry as almost…kind, and he failed to keep a grin off his face. Why hadn't McGonagall been this forthcoming and useful? She was his Head of House! "Thank you, sir, I can't tell you how much I appreciate you offering your time up to help me. Knowing what I do now about why we're sorted into the Houses we are, I wonder if the Sorting Hat wasn't right to want to put me in Slytherin."

Snape raised an eyebrow, but gestured for Harry to return to cleaning. The younger wizard did so, happy to have something to do with his hands as he thought over everything they'd just discussed. Perhaps, if Snape could look past House prejudice to help a student he already disliked, Ron was wrong about who Slytherins really were at the core. This thought made Harry stifle a laugh, realizing that this sort of thinking was precisely what Snape had been talking about. Teachers didn't just teach subjects, they taught students to think for themselves, and to pursue untouched avenues of thought.