McGonagall knocked shortly on the door to the headmaster's offfice and went in immediately without bothering to wait for an answer.  As was to be expected, Severus Snape was pacing in the office agitatedly while Dumbledore was sitting in his usual chair, a cup of tea in front of him, and seeming to find the situation more amusing than anything else.

‘Ah, Minerva, please do come in and take a seat!' he said and pointed to one of the armchairs in front of his desk. ‘Maybe if you sit down, Severus can be persuaded, too, to cease wearing down both his shoe soles and my carpet.'

Snape shot him a dark look but actually sat down in the seat next to his older colleague, who evenly asked the headmaster,

‘I take it Severus has already filled you in?'

‘Indeed he has', said Dumbledore and leaned back comfortably.

Snape sneered at his Gryffindor colleague. ‘So what about Potter? Is he in his Common Room where he belongs? Or do we have to expect more escapades from him tonight?'

McGonagall didn't deign to answer this. Instead she just looked at Dumbledore and spoke as if she hadn't heard Snape's outburst, ‘Yes, thank you, Albus, I would like a cup as well.'

The Headmaster's eyes were twinkling as he filled a cup and let it float over to his colleague.

‘So,' he said, ‘I take it you have spoken to Harry; what did he say?'

‘That he was sorry. Though I have to admit when he didn't answer at once when asked about his motivation I didn't insist. Knowing Severus and his relationship with Mr Potter,' she glared at her younger colleague and he glared back, ‘I had no doubt that you would have to talk to him anyway, so I thought I'd leave it up to you to find out his motives.'

‘Motives!' Snape exploded. ‘I keep hearing "motives"! I couldn't care less about his motives! I demand an exemplary punishment!'

‘Severus would you please calm down!' Minerva snapped. ‘Yes, Mr Potter has broken school rules today. Yes, he deserves punishment. But you are missing all sense of proportion right now! After all, he hasn't done any harm. It was just a harmless prank.'

‘A harmless prank', Snape repeated sarcastically. ‘I can only imagine your tirades if the roles were reversed and a Slytherin, say Malfoy, had sneaked into the Gryffindor Common room and spied on Potter. Then of course it would have been a vicious and underhanded attack on your precious Gryffindors. Sense of proportion, you said! Are you sure you aren't applying  double standards here?'

‘You're being ridiculous!'

‘Am I really? What I see is that whenever a Gryffindor breaks a rule it is a harmless prank, whereas when a Slytherin does the same thing, the worst motives are assigned!'

This was more than Minerva was willing to hear. 'Severus Snape. I will not sit here and let you tell me that I am biased and treat the students unfairly, favouring my own house! Coming from you that is a bit rich!'

Dumbledore cleared his throat. 'If you'd allow me to say something...' Two pairs of eyes turned to him. His two colleagues had almost forgotten that he was there, so immersed had they been in their argument. Both nodded stiffly, altough a bit sheepishly.

‘Thank you,' the old wizard said evenly. ‘I see your point, Severus, and agree that it is very unfortunate that there exist wide-spread prejudices against Slytherins. Having been a Gryffindor I am well aware that I sometimes have to struggle to act unbiased myself. However, I think that Minerva is above reproach when it comes to the question how she treats the students.'

Snape inclined his head. ‘I apologize.'

‘Accepted,' Minerva said crisply.

‘Very well,' Dumbledore continued. ‘Perhaps we can now get back to our original topic of Harry's actions and what response we should make. Let me summarize the facts: Harry was out of his common room after hours. He went into the Slytherin common room, where he has no business to be, and he was invisible. While the first two issues might each warrant a detention, the third is quite a different matter. So what kind of punishment do you have in mind, Severus?'

‘It all sounds very well when you put it like that, Albus. But you are missing that he was spying on his classmates, and he was doing it at the place where they are meant to be most comfortable. It is one thing when the Weasley twins try to sneak in to see if they can manage it. It is quite another to use a powerful magical artefact to conceal oneself in such a despicable way! I will not permit everyone to think that Slytherins are a suspicious lot and so there is no harm in spying on us!' Snape finished angrily, quite oblivious to the irony of his complaining about someone else's spying activities.

Dumbledore nodded. ‘Which brings us back to the omnipresent prejudices the members of different houses have against each other. I see your point, Severus, but please don't forget that these prejudices are not Harry's fault. He is thirteen after all, and he is a product of his environment. Alas, Harry's attitude is not that unusual, as you yourself point out. He needs our understanding.'

‘What Potter needs is a much tighter rein!' Snape snapped.

Dumbledore nodded thoughtfully. ‘Maybe, Severus. Maybe he does. However, I ask you to see what he did merely as a rash idea from an immature boy. Well, I have an idea what we can do so that this evening's little episode has a positive impact on Harry - and perhaps quite a few others.'

He looked through twinkling eyes at his two colleagues who silently waited for him to proceed. ‘I think we should tranfer Harry - for a limited time of course - to Slytherin.'

‘What!!' Both McGonagall and Snape leapt to their feet simultaneously.

McGonagall was the first to find her voice. ‘And what is the sense behind that? You kept saying that Mr Potter is acting like any boy of his age, yet in the same breath you suggest that he has forfeited his place in Gryffindor? And what good shall it do, separating him from his friends? Do you want to make him completely miserable? And what is the point of all this anyway? Is it simply to throw Severus a bone so that as Harry's new head of house he can finally punish Mr Potter as he sees fit?'

‘Oh please!' Snape scoffed. ‘I can well live without this kind of favour! I honestly hope that I misunderstood you, Albus, for if I didn't, you just delivered he biggest insult that I have heard for many years. Are you meaning to tell me that you consider it to be a punishment to be in Slytherin, as something inferior to Gryffindor? What do you think that kind of message would send to the students?'

‘I agree with you, Severus,' McGonagall said, looking reproachfully at the headmaster.' Each house has its own merits, and it is an old and good tradition to sort the students according to their personality into the house where they would fit best.'

Dumbledore pensievely shook his head. ‘An old tradition, yes, Minerva, but whether it is good I sometimes have my doubts. I often think we sort too soon, but at the moment that is neither here nor there.' His gaze wandered to Severus before he continued. ‘But perhaps it will set your minds at ease if I tell you that the sorting hat indeed put Harry into Gryffindor, but only after Harry had talked it out of placing him in Slytherin, which, as Harry told me himself was the hat's original idea.'

A tense silence followed, eventually broken by Minerva.

‘He is a Parselmouth', she admitted thoughtfully, ‘so it makes sense in a way. But the rest of him is a Gryffindor, if there ever was one! And even if he was not,' she added vehemently, ‘what good would it do to make him change houses now? He is happy in Gryffindor!'

‘I agree with Minerva, albeit for different reasons. I have my house to consider. Potter wouldn't fit in and is likely to cause utter chaos. I fail to see what "positive effects", as you put it, you expect to see, Albus,' said Snape.

‘I am glad you asked, because I was going to come to that now.' Dumbledore looked at them over the rim of his glasses. ‘The relationships between members of the four different houses is not always ideal, and I think you will both agree that between Slytherin and Gryffindor it's the worst. So I believe if Harry succeeds in making friends in both houses, this may be the start for a great improvement. And why shouldn't he? The sorting hat told him he would do well in Slytherin, so I have no cause to believe the opposite. And there is no denying he has shown interest in Slytherin, so we might well grant him his wish  and let him learn more about life in Slytherin.'

McGonagall was far from convinced.  ‘Albus, stop being so hypocritical! "Grant him his wish  and let him learn more about life in Slytherin", indeed! You know as well as I do that even though Mr Potter was undoubtedly curious tonight, it was not about life in Slytherin but surely about something specific about his classmates! Or maybe it was just the preparation of some silly prank.'

She took a deep breath and continued in a sharp tone.  ‘What you say about this theoretical, for lack of a better word, "internship" in Slytherin being a means to improve inter-house relations, well, I suppose it might work. It might not. But even if it did, it's not fair to Harry to use him as a tool, without taking his personal interests into account. For goodness sake, he is a mere boy, not some sort of ambassador!'

Dumbledore raised his hands to stop her agitated speech. His face had become sombre and his eyes had lost their twinkling.

‘Yes, Minerva, you are correct that he is not some sort of ambassador, but no, as much as it pains me to say this, he is not a mere boy. You both know that I am convinced that Voldemort shall return, and when he comes back, Harry will be his most important target. And in those dark days, Harry will need all the allies he can possibly have. Severus, you know as well as I do that when the day comes that Voldemort returns, many of your house will be tempted - or perhaps pressured - to follow him. If even one of them has befriended Harry and consequently reconsiders his choices, I shall think this experiment has been worth while.'

A heavy silence followed his words. Snape and McGonagall looked at one another uncertainly.

‘So,' MacGonagall asked slowly and reproachfully, ‘this plan of yours actually has nothing to do with what Harrry did today, does it? You wanted to do this anyway!'

‘The idea had entered my mind,' Dumbledore admitted, ‘but I wouldn't have done it without tonight's events. I have to admit that I am quite pleased that Harry has given me the pretext to implement my idea.  And don't look at me like that, Minerva. Harry will be fine. I repeat, the sorting hat told him he would do well in Slytherin.'

Snape's voice was hardly more than a whisper. ‘Whatever options the sorting hat may have debated with the boy, its final decision was Gryffindor. I still think it's a disastrous idea to overrule the hat on the only issue of its authority and self-righteously place this defiant, unruly and stubborn boy into my house! You cannot - '

Dumbledore interrupted him. ‘As for stubborn, I can only say that if he were less stubborn you would have had him in your house for the past two years. And as for unruly, well, you said yourself that he needed a tighter rein. So this is your chance, isn't it? To take him in hand yourself?'

‘How tempting, Albus.' Snape said drily. ‘Knowing you, I assume that continuing this discussion is pointless and you have already decided?'

Dumbledore made an apologetic gesture. ‘Yes, I have, although I still hope that I might actually convince you of my idea's merit...'

‘Well Albus, since you have so many good ideas, maybe you could suggest what I should tell my students,' Snape said coolly. ‘I promised I would see to it that Potter was punished. So what am I supposed to say, "The headmaster has decided that being with you is Potter's punishment ?" ‘

Dumbledore chuckled. ‘Well, Severus, maybe you should show a bit more tact. Why can't you say that I considered the blows that Harry received from your outraged students sufficient punishment? As for Harry changing house, blame it all on me, say I was thrilled by Harry's interest and and thought that as the first Parselmouth at Hogwarts in fifty years I thought he should be given the chance to experience Salazar's house. You have such a good relationship with the members of your house, Severus, I am sure you'll find the right words.'

‘Well, thank you so much, Albus', said Snape sarcastically.

Dumbledore turned to the Gryffindore head of house. ‘So when do you plan on telling Harry?' he asked.

‘Not at all!' she said, her lips in a thin line. ‘This is your idea, and I still think it's not one of your better ones, so you'll tell him yourself!'

Dumbledore nodded. ‘Fair enough. Well, tomorrow after breakfast then, no need to let him stew in anticipation any longer than necessary. Is there anything else we need to talk about tonight?'

‘Yes', said Snape slowly. ‘You said a "limited time". What length are you contemplating? If you plan for Potter to befriend people we cannot be talking about a fortnight.'

‘No', Dumbledore agreed. ‘But we don't have to decide this now, do we? I'd suggest Harrry starts the day after tomorrrow, Sunday, after dinner.'

‘Then I want to make one thing clear.' Snape looked intently first at Dumbledore, then at McGonagall. ‘If I accept him in my house, he will be a regulat member there, with all rights and duties pertaining thereto. I will not have someone with special status in my house.'

Dumbledore nodded approvingly. ‘I would not expect anything different from you, Severus.'