Neville Longbottom hated Potions class. Which, as the same was true of roughly three-quarters of the student body, was hardly a surprise. What was a surprise, however, is that Neville was rather extrodinarily fond of the subject matter, and really quite good at it. Well, as long as a certain snarky, mean-spirited potions master was nowhere to be seen. This explains how Neville was in the NEWT level sixth year Potions class, having gained the required grade of "Outstanding" - in a subject he was universally known to be dismal in. It also explains, in a roundabout way, how any sixth year in a NEWT Potions class could confuse powdered Blackrose root with powdered Blackrose leaves. It does not, unfortunately, explain why a professor would be intimidating a promising student into making a horrible mistake. Nor does it explain why said professor made no move to stop him.
One moment, Neville stood in the corner of the room, trembling under the gaze of the eternally malevolent professor Snape; the next, a fantastically reddish-black potion (it was supposed to be blue) was erupting upon Neville and the nearest students. Neville was hit first, and strongest. Professor Snape, to Neville's deep dissatisfaction, was pushed out of the way by Draco; one of only two people in the room with the reaction speed to do something. Even if he was the most unlikely person to ever see risk himself for another, he had done so, and he was actually hit worse than Neville himself. On either side of Neville, the other two at his table (the only house-members Neville had in this class) were hit nearly as much as he was. The only other with reflexes good enough to do anything, the second seeker in the room, had managed to react to the explosion in the seconds given. He could have used his phenomenal reaction time to dive for cover; could have, except that he didn't even think of it.
Always the hero, the boy was. Even more so since he'd been unable to save his godfather last spring. He didn't TRY to be a hero, at least not anymore. It wasn't the same as it had once been, a concious seeking out of adventure, of a chance to prove himself. It was the same action, in the end; it was the reason behind it that was so far different. No one noticed. Perhaps because the behaviour remained the same, or perhaps because they wouldn't understand it, even if they heard the words. The boy hero, the boy-who-lived, had made a very subtle but important paradigm shift. He no longer thought of others first because he cared more about them than he did for himself. He simply valued himself less than anyone else.
The difference is deep, fundamental. It is something many have failed to grasp over the course of the ages. A man may give his life for another, and have the sacrafice mean nothing, if he does not posess love. And no one can understand, can value another enough to love them, unless he can first understand, value, and love himself. Yet still, in the end, the action was the same; Harry Potter cast a shielding charm around the cauldron, expanded large enough that none of the potion already flying would be beyond it, yet small enough to keep the class from being contaminated. The class, that is, excluding Neville, Draco, Hermione, and himself.
Time seemed to stand still. Each of the four had a moments' contemplation after being struck by the failed potion, it was the endless sort of moment in time between when somethng catastrophic happens and when the consequences are felt.
Harry spared no time for thoughts of all the students he'd saved, he only thought of those who had been hit, hoping that the potion wouldn't kill them, or that, if it did, it would take him with it; he had no desire to wake again only to find the blood of another, or worst still, three others, on his hands. He felt badly for the injuries they would surely endure because he wasn't fast enough, wasn't strong enough. He felt even worse for half-wishing it would kill him, putting an end to misery, as his death would doom the world.
Hermione, the other Gryffindor hit by Neville's catastrophe, took the time to contemplate what the results of the accidentally-created potion could possibly be. When the potion hit, she'd been startled away from her own brewing, and recognized the powder in Neville's hands. The broad-ranging knowlegde she posessed enabled a quick assesment of the chemical and magical reactions. This potion, she knew, was meant to provide a glimpse of the immediate future; so immediate, that it was simply considered a sort of truth-revealing potion, able to show what would be (was) happening.
The potion was well known to Hermione, as it was at the forefront of research in time travel, a subject dear to her since the time-turner in the third year. The potion-brewer could either watch the surface of the potion to see a scene play out before him, or touch it and be transported to that event to witness it firsthand. Hermione remembered that the potion would show the most important event related to the potion maker, that would be (was currently) occuring. It was so important to time travel research, because, however miniscule the amount of time it traveled, it was the only known method of travelling forward.
Draco's thoughts were frighteninly similar to Hermione's, had either of them known. He had a more intimate knowledge of magical plantae, however, and knew that the roots and leaves of a thing typically had directly opposing results. Since Neville had added roots instead of leaves, the potion should provide a glimpse of the past. The problem was that Blackrose petals were already part of the potion. The flowers or fruits of a plant tended to have vastly amplifying effects when combined with the roots. The sort of vastly amplifying that could change a mild warming potion into an explosion that would level city blocks, or a potion meant to help one dream into a potion that brought ones' dreams into the realm of reality. Which is why, when he saw what Neville had done, he threw his godfather out of the path of the potion in exchange for himself.
An annoyingly Gryiffindor thing to do, true, but Severus was the only one who'd ever given a damn what happened to him. He'd given Draco honest answers when he'd asked questions about the Dark Lord, or about anything else. Instead of simply spouting pureblood propeganda, Severus had given him real, straight answers about muggles. He had always backed his answers with reasoning and logic instead of sensationalism or "because I said so", a thing for which Draco was profoundly grateful. Often times, Severus had even presented both sides of an argument, and told Draco he was old enough to simply see what was, and draw his own conclusions from it. Quite honestly, Draco wasn't entirely sure yet what those conclusions would be, though he knew he'd have to decide soon, as he came of age in two more months. He knew one thing for sure, though, and that was that he wasn't about to let his godfather die because of an idiot Gryffindor, which was most likely going to be the end result of this catastrophe.
Neville's thoughts weren't nearly so depressing as Harry's, or so analytical as Draco's or Hermione's. They were fairly simple. On the one hand, he'd managed to blow up a cauldron again. He hated when that happened, and he hated Professor Snape even more for encouraging it to happen. On the other hand, he was quite used to it, and at least this time the Professor would be suffering for his part in the accident, through Draco's misery, nearly as much as Neville himself would be. He was only slightly worried for his classmates and himself; after all, nothing he'd done before had resulted in anything worse than a visit to the hospital wing. He did wish, however, that Harry and Hermione hadn't been hit.
For each of the four, these thoughts were their universe at the time, even though these thoughts were only a mask for what was truly in thier hearts. Not one of them was truly worried about the consequences this accident would have upon themselves. In this, they were fundamentally the same. For each one, the analytical withdrawl from what was going on was merely a relief from a soul deep ache for something more than what they had. To the world, Harry was famous, Draco was spoiled rotten, Hermione was a perfect know-it-all, and Neville was the proud son of one of the oldest and best known wizarding families. In reality, however true these things were, they were only superficial. Neither fame, fortune, intelligence, or power could fill the place of love. In that endless moment, unknown to the four but no less important for being unannounced, each was bonded to the others by this sameness.
However endless the moment seemed, it did have an ending. An ending that was more final than any of them could possibly have guessed. Had they known, they would have feared. Not for their lives, nor exactly for the lives of their classmates and friends, but for something much more horrific than the loss of either of those things could ever be. For, in that moment, the world they knew simply ceased to exist.
Wizards, much as muggles, think they understand the way things interact in their world. The understanding in the wizarding world is as Draco thought it to be; combining the flowers and the roots of a thing in a single potion make it do the same thing only much stronger. This is only half the truth. While the combination does, in fact, make the intended result a great deal stronger, it also purifies it. Or, rather, it purifies what magic percieves to be the intention of the potion as a whole. Magic is sentient, in this sense, able to respond in a way that isn't merely dependant upon the way things ought to be; that is, in the end, what makes it magic.
So it is, that magic saw this potion. A potion for time-travel slightly forwards, to the most important event occuring when you get there. Except that the direction of travel was reversed, and there was that root-petal combination. Purifying and amplifying. In the purest sense, or so magic saw, the potion was to link the potion brewer to the most important event related to the brewer. The other intent, the reversed intent, was to pick the important event from the past. Magic saw Neville, saw the timeline as a whole, and picked an event. Then, seeing the result, it amplified one last thing, and was complete.