As the Snapes began their conversation, Harry wondered briefly if he could make out what they were saying, but lip reading had never been his forte, and after a moment, his attention was caught by the sight of some movement behind Alium-Snape. Harry's doppelganger had recommenced sorting his box of books, and seemed to be rather intent upon his task. Casting his eyes about, Harry wondered if the same box existed in his world. It was difficult to tell; all were covered in dust, and the scene was half-obscured by Alium-Snape, who seemed to be having a rather heated discussion with his own counterpart. Just as Harry was starting to get slightly frustrated with trying to locate the correct box, Alium-Harry's gaze flickered up to the mirror, and Harry waved to catch his alternate self's eye. The boy saw him staring and raised an eyebrow in question, whereupon Harry gestured at the boxes around himself in enquiry.

The boy in the Alium nodded his comprehension and raised a hand to wipe the dust off the box he was currently delving through. Under the layer of dirt and grime, the box was apparently a dull red colour. This narrowed the field somewhat, and a short search yielded the box in question. As he gripped the edges of the box with his fingertips, prising the unwilling lid up and off, the scent of mildew and ancient pages launched into the air. It was absolutely brimming with books, and Harry gestured helplessly to his alternate self, who rolled his eyes good-naturedly, and picked one off the pile beside him to hold aloft so Harry could see the title. Harry thought it was the one he'd seen given to Alium-Snape earlier. He couldn't make out the title, but the cover was black, with a golden sheen of cursive lettering emblazoned across the front.

He rifled through his own box until he found what he thought was the right book and held it up for inspection. His alternate self nodded, and Harry gripped it tightly, looking down at the cover as he did so. "Pessimus magicae," he muttered. His Latin wasn't brilliant- Hermione insisted that a study of Latin was incredibly helpful but he'd never found the need. With a sinking heart, he flicked through the tome and confirmed his first instinct that it was, indeed, written entirely in the dead language. He looked up to his counterpart impatiently, frustrated beyond belief. From the dawning look of understanding on the face of the boy in the Alium, he thought his message had been received. Clearly, his counterpart had no such difficulty reading Latin.

The boy in the Alium pursed his lips and flicked through the book, straight to the back, where his expression brightened. He then glanced across at his- well, his guardian, Harry supposed- and, seeing that both Snapes were now engaged in a bizarre staring match, he raised his wand and wrote lettering in the air. Harry shivered- it was too reminiscent of Riddle in the Chamber of Secrets. The lettering read, 'Tap Anglicus'.

Curious, Harry immediately imitated the other boy, flicking to the back of the book, where there were two words on the inside cover- Gallico and Anglicus. Harry tapped the latter, shrugging at his counterpart when he opened the book to a random page in the middle to find that the book was still in Latin, only to see the other boy raise his eyebrows and point to his wand, a look of complete incredulity on his face. Harry felt his cheeks warm slightly; he could almost hear the words,- Are you a wizard or what?

Harry tapped the word again, with his wand this time, and then the book warmed briefly in his hands. When he flicked back through it, he was pleased to find that the book was now in English. He smiled his gratitude rather sheepishly at the boy across from him, who smirked.

He was just checking for an index (he had found, to his irritation, that older wizarding texts often lacked these) when he realised he could once again hear movement from Snape. It appeared that the two professors had finished their conversation.

"Thank you for waiting, Mr Potter," said Alium-Snape, with an unmistakable air of satisfaction. "I'm content in the knowledge that you will have support in your own world going forwards."

Harry surreptitiously tucked his book underneath his jumper (not the first time his baggy attire had come in useful) before rising from his knees and turning his head to look towards his potions teacher doubtfully- Support? Snape?- but said nothing. He crossed the room carefully to stand beside his potions master, looking into the Alium, watching as his counterpart mirrored his actions. Alium-Snape continued to talk. "Now, are there any other questions you still have, Mr Potter? Once your curiosity is fully satisfied, the Alium should release us all to go our separate ways. I shall be destroying this version as soon as our door unlocks, and I've advised your professor to destroy your version too, once the connection ends."

"Hang on," said Harry, furrowing his brow, "Why does it depend on me?"

"Because, Mr Potter" explained Alium-Snape, shooting what looked like a warning glance at his own counterpart, who had opened his mouth as if to respond, "The Alium was awoken by you. Only when you feel ready to leave will it release the rest of us."

Harry looked at the people in the mirror, feeling a sense of embarrassment, "I'm very sorry to have kept you," he said sincerely. I didn't mean to."

"Harry!" interjected his Slytherin self, kindly. "It's fine. I'm actually very glad that we met you. Hopefully, you know enough now to get old Voldyshorts defeated sooner rather than later. But if you have any other questions, now's the time."

Harry grinned. Voldyshorts was definitely his new go-to. He thought for a moment- questions, questions... Oh! He turned curiously to the window Harry. "Why did you listen to the sorting hat, anyway?"

Alium-Harry shrugged. "It was pretty persuasive. What did it say to you?"

Harry had no difficulty remembering; he'd thought about it many times over the years. "It told me I could be great and that Slytherin would help me on the way to greatness."

Harry's other self looked surprised by this. "That's it? I'm not surprised you weren't convinced by that!" he exclaimed. "It definitely tried harder with me. It told me off, if you'd believe that!" He shook his head, the corners of his mouth betraying amusement as he reminisced. "I was repeating, 'Not Slytherin, not Slytherin' and it said, "Not Slytherin, eh? I'm disappointed in you, young Potter. I'd have thought you knew better than to put so much stock in the prejudices of others, given your own upbringing." Alium-Harry smiled ruefully.

"But," Harry protested, "it wasn't about prejudice!"

"Wasn't it?" queried his alternate self, mildly.

"No!" insisted Harry, "It's a fact that there are more dark wizards from Slytherin!"

"True to an extent," conceded Alium-Harry, "but did you know that at the time?"

"Of course- Hagrid told me!"

"I don't know what your Hagrid told you," the boy facing him said, plainly, "but mine told me there isn't t a wizard or witch who went bad who wasn't in Slytherin. Which is clearly a load of old rubbish."

"Voldemort was a Slytherin!" argued Harry.

"As was Merlin," countered Alium-Harry, a deliberate note of boredom in his voice suggesting that he'd had to defend his house on numerous occasions, and was well-used to it. "It's prejudiced to use one bad example to judge the rest of a group and you know it."

"Well," Harry said, thinking back to the reasons he'd had for not wanting to go into Slytherin house, "Malfoy was a git in Madam Malkin's and when I met him again on the train he was awful to Ron. And he kept going on about Slytherin. I didn't want to be in his house." Harry noticed that the man beside him had raised an eyebrow at this, and he fought down a flush of embarrassment.

"Again, one bad example," noted Alium-Harry, a hint of kindness in his voice this time. "That's essentially the conversation I had with the sorting hat. It pointed out that no school house is inherently evil. Then it said it had been sorting wizards and witches for a thousand years and it felt that I would be better off in Slytherin than anywhere else, though it would put me elsewhere if I wanted. It asked me to trust it." He shrugged. "In the end, I said OK."

"So basically," said Harry, in disbelief, "It's the hat's fault. The Hat just accepted my request! I only got that thing about Slytherin helping me on my way to greatness and an, 'Oh well, if you're sure, better be Gryffindor!'"

Alium-Harry frowned. "Worst luck, Harry, sorry."

Harry shook his head. "It's OK. Nothing to be done about it now, at any rate, and I've been happy in Gryffindor." He stalled for a moment- he wasn't quite willing to let them go just yet. "Oh, another question, how did you find out about the horcruxes?"

Alium-Harry responded, "I don't think I knew about them until last year, when Severus told me."

"Correct," Alium-Snape confirmed, "But I was informed, as Harry's guardian, shortly after the headmaster discovered the diary in Harry's second year. I've been working with him to identify and track down horcruxes since. Having a functional one to experiment with was invaluable. That's how we created the identification spell I just taught your professor, which is what led to the identification of Harry's scar as a horcrux." He turned to Snape, his expression pensive, "Has the headmaster confided the knowledge of horcruxes to you?"

Snape shook his head in denial. His alternate self's eyes seemed to darken in thought. "It seems to me that your headmaster is more determined to keep his machinations to himself than ours. I wonder if it's possible he interfered with the hat in some way."

Harry shook his head in denial, studiously ignoring the ice that trickled down his spine at the thought. He could think of nothing else to ask and, after a moment, admitted as much. The alternate pair wasted no time in bidding them farewell.

"If that's truly all you have to ask, Harry, the door should open for you and your professor now. I imagine that the connection will end when Harry leaves the room, Professor Snape, if you'd like to take the opportunity to destroy the window." said Alium-Snape, to which his counterpart nodded.

"Wait, wait!" objected Harry, suddenly feeling a sense of impending loss, "You can't destroy it! It's mine, and it's been really useful- what if another version of us knows how to get rid of this?" He pointed to his scar.

"And that," Alium-Snape commented, gently, "is why the Alium is dangerous, Harry. It will never show the answers you consciously seek, just drive you mad in search of them, showing you worlds where you are happier, safer, better cared for." He smiled sadly at Harry. "It would only serve to increase your dissatisfaction with your own life, cause you to feel a sense of failure and self-recrimination, as indeed this encounter with it has done. You are lucky that I happened to be close enough to Harry when this started, as it meant that I was able to call your professor and explain to him. This was not a typical experience with the Alium, Harry- it is not safe to use as a tool for intelligence gathering."

"But, sir," countered Harry, desperately, "What about Dumbledore? Won't he want to try it?"

"Professor Dumbledore," his own Snape responded, snidely, "has recently proven himself less capable of self-restraint in the presence of a magical artefact than one might hope him to be."

Alium-Snape shot a look of exasperation at his counterpart before adding, in a softer tone, "The headmaster has some… intense regrets that I am not at liberty to disclose to you, but I agree with your professor when he suggests that the Alium might well prove problematic for Professor Dumbledore."

Harry crossed his arms stubbornly. 'It's mine and I still think we should keep it. It might be useful, like the Mirror of Erised was."

"And, as our resident expert in the Dark Arts and their artefacts, your word is, of course, law," drawled Snape, sardonically.

Harry threw a scathing look at the man beside him. "As owner of this house and everything in it, my word is law, yes!" he snarled, temper mounting rapidly.

Remembering his other self suddenly, he turned to face the boy. "What about you?" he demanded. "Are you going to let him," he gestured at Snape's counterpart, "destroy your stuff? He didn't even ask!"

Alium-Harry smiled ruefully at this. "Oh, I didn't expect him to," he said lightly. "He only ever asks me if he's willing to accept my answer. He doesn't believe in offering an illusion of choice," he continued, putting on a deeper tone of voice for the last, making it clear that he was parroting his guardian. The boy shrugged.

Harry was somewhat dismayed by the way in which his alternate self capitulated so quickly to Alium-Snape's unreasonable demands. Something must have shown in his expression, because, after a glance at his face, Alium-Harry directed his attention to Snape standing beside Harry.

"Do you think you could give us a minute?" Snape huffed an impatient breath, before grabbing Harry's shoulder and yanking him back a pace or so from the Alium.

"Do not touch that unless you wish to be trapped in there for eternity, Potter," he snarled, before whirling around and stalking to the other side of the room. Alium-Harry watched him go with a roll of his eyes, before directing his attention to Harry once more.

"I know it's a strange idea, but generally I've found that Severus knows what he's talking about, even when we disagree." He smirked at Harry's raised eyebrows and pointedly ignored Alium-Snape's smug expression. "It's different for me," he continued, "because he's my guardian, so he's got the right to do what's best for me whether I agree or not. One of the downsides of having a guardian who both knows and cares what's going on in my life," he added, dryly, "But, even though your Snape seems a pretty nasty piece of work," here, Harry nodded in firm agreement, "from what I can see, I reckon he's still intelligent, and he probably has good enough instincts that you can take his advice as fairly sound. Usually, if he thinks something's a good idea, it probably is, assuming he's got all the relevant information. I think you can trust him. I'm trusting mine on this, so, even though the Alium is technically my property, if Severus thinks it'd better be destroyed, than I guess that's what we'll do." Harry frowned at this, but said nothing. After a moment, Snape was beckoned back to join them. Harry was surprised when the man limited his ire at being banished to the side of the room to a sneering expression. Harry had been expecting a small tirade about arrogance and not considering the time of others to be important, or at least a snide comment about precious Potter's privacy. Maybe the man was tired. He grudgingly informed Snape that he could destroy the Alium, and saw the other Snape nod in approval.

"Well then, it's been an honour to have met you both," said the Alium-Snape, once they were all together once more. Best of luck!"

"And to you, also," nodded Snape, almost cordially, shocking Harry, whose eyes he met as he turned.

"Off with you then, Potter," he dismissed Harry, who gave his final parting wishes and thanks to his alternate self and the boy's father, before heading to the exit.

"Wait," he paused suddenly, his door on the cool brass of its handle, as he turned back to Alium-Harry, "One more question; do you ever worry that Mum and Dad would be disappointed that you sorted the way you did?"

In the Alium, Harry shook his head. Alium-Snape elaborated for him. "Harry asked me that question once, when he was just 11 years old, and I will tell you now what I told him then. 'You underestimate how much your parents loved you if you believe they'd have thought badly of you for something as inconsequential as sorting. The sorting hat's choice may have an impact on how you are perceived by others, but it does not alter who you are.'"

Harry nodded in acknowledgement before turning the handle of the door, which opened into the hall, where half of the Order was waiting for him.