The tardiness rate on the first day of classes at Hogwarts exceeded forty percent.
The cause was the school's numerous complex and bewildering architectural quirks. Of its one hundred and forty-two staircases, some were unnecessarily grand and wide, others were barely wide enough for one person, some led to entirely different destinations on Fridays, and others had steps that simply vanished underfoot without warning.
The doors were equally unreasonable: some refused to open unless addressed politely, others required tickling in a very precise spot, and some were not doors at all but solid walls that merely looked like them.
The portrait subjects were forever visiting one another's frames, making them useless as landmarks. Peeves the poltergeist, for his part, actively contributed to the chaos by gleefully ambushing students at every opportunity.
On this particular morning, however, Peeves was encountering the worst student he had ever had the misfortune of meeting.
He had been struck hard on the back of the head and sent rolling miserably across the floor. Before he could even manage a groan, the girl who had kicked him crossed the distance between them, seized him by the head, and hauled him upright.
The fact that she had grabbed him at all, a poltergeist with no proper physical form — was enough to bewilder him entirely.
"Listen here, Poltergeist. You had the nerve to throw rubbish at me." Mirabelle smiled pleasantly down at him. "I, Mirabelle, am going to give you a truly wonderful reward for that."
"Wh— why can you touch me? How are you touching me—?"
The one gripping Peeves' head was Mirabelle Beresford, first-year Slytherin student.
The reason she could hold him at all was the magical technique she was applying. Human hands could not ordinarily make contact with ghosts or poltergeists, but magic was another matter.
By gathering raw magical energy into her palms, she was able to grip him directly. It was a trick only Mirabelle, already capable of wandless magic, could manage, and she felt no particular obligation to explain it to anyone.
"Rejoice, Poltergeist. I came across a rather fitting spell in the library just the other day." Her smile widened. "You will make an excellent test subject."
"...What spell?"
"An exorcism. Used to drive away ghosts and similar entities."
A spell that was his natural enemy.
Under ordinary circumstances it would simply repel a ghost from a distance, but being held at point-blank range while it was cast was an entirely different matter. Peeves tried to wrench himself free in a panic, but her grip did not give so much as a fraction.
The incantation came, calm and precise.
"Expellianima!"
A white flash scorched directly through Peeves' head. His body convulsed, thrashing wildly in her hand. It was not possible to kill Peeves, he was not even a ghost in the strictest sense, but the spell was proving extremely effective regardless. Perhaps "kill" was the wrong word. Perhaps "send on" was more accurate.
"Ah—"
"Wonderful. Go on and disappear, why don't you. It would be genuinely interesting to find out whether this spell can make a poltergeist cease to exist entirely."
"Help, please, help me! I swear I won't play any more tricks!"
This was, strictly speaking, an experiment. If a spell designed only to drive ghosts away was applied at point-blank range, how much did its effect amplify? Could it reach the threshold required to genuinely end a higher-order poltergeist? Or would it only continue to torment without finishing the job? The question was legitimately fascinating.
Peeves' plea, however, sparked a rather more practical idea.
"Will you swear never to defy me again?"
"I swear! I swear it!"
"Will you obey me without condition?"
"That's... that's a bit much—"
The moment Peeves hesitated, Mirabelle's free hand closed around his throat.
The incantation came again.
The white flash intensified, burning through him as though he were dry paper.
"ABABABABABA, stop, stop it! Am I actually going to disappear?!"
"Choose, then. Disappear, or obey."
"I'll obey! I'll do whatever you say! Just stop!"
Mirabelle smiled with satisfaction at the sound of Peeves' voice, thick with something very close to tears. She released him and dropped him to the floor as though discarding something she no longer needed. He lay there twitching. She placed one foot lightly on his head.
"Good. Your first order: clean up every piece of rubbish you have scattered around this school."
"...yes..."
He sounded thoroughly defeated. Mirabelle gave a small nod, swept her robe around her, and turned.
Edith Rynagle was visible at the far end of the corridor, pressed into the shadows of a corner and trembling visibly.
Mirabelle's expression shifted into something almost warm.
"What is it, Rynagle? Don't hide there, come out. We have Potions next with Professor Snape, we ought to get down to the dungeons."
Edith emerged from the corner on unsteady legs. "...Mirabelle, you're utterly merciless. I'm starting to feel sorry for Peeves."
"That is what he gets for throwing rubbish at me."
The Potions lesson was a joint class with Gryffindor.
Mirabelle and Edith descended to the dungeons and entered a room that suited its head of house perfectly. The stone walls were lined from floor to ceiling with glass jars, each containing some organism suspended in murky liquid.
It was dim, cold, and faintly oppressive, precisely the environment one would design if one wished students to feel slightly unwelcome.
Snape was already at the front of the room. Once he had confirmed that all students were present, he began the register.
When he reached Harry's name, he paused for just a moment before speaking in a voice that was soft and unpleasant in equal measure.
"Ah, yes. Harry Potter. Our new celebrity."
The Slytherin students chuckled, and Harry received it all in rigid silence.
After completing the register, Snape addressed the class on what Potions entailed, not the crude waving of wands, but a subtle science and exacting art. The speech was, admittedly, rather good. Then he ended it by snapping "Potter!" and pointing his wand at Harry without warning.
"What would I get if I added powdered root of asphodel to an infusion of wormwood?"
Harry, caught completely off guard, stared back at him. He could not answer. Most of the class probably could not, no lesson had yet been taught. Hermione, predictably, was the exception; her hand shot up at once. Snape did not so much as glance at her.
"I don't know."
"Clearly, fame isn't everything."
As Mirabelle listened to this exchange, she turned something over in her mind.
Snape favoured Slytherin, that much was already apparent. If a Slytherin student raised their hand rather than Hermione, a Gryffindor, would he call on them instead? And would he award points accordingly?
Mirabelle was not, as a rule, particularly motivated by house points. But she was thinking about something specific.
At the end of the year, Dumbledore had made a point of awarding the House Cup to Gryffindor with blatant last-minute additions to their tally, engineered specifically around Harry. Mirabelle had found that irritating even in the original story. She found it considerably more interesting now that she was in a position to interfere.
What would happen if she significantly increased Slytherin's points beyond what the original timeline had produced? Would Dumbledore award Gryffindor what they had genuinely earned and allow Slytherin to win, suggesting a degree of genuine fairness? Or would he simply add even more points to Gryffindor to force the result he wanted, which would reveal something far more valuable: an emotional investment in Harry's elevation that could be read as a weakness.
'Hmm... worth trying. It would also make for a rather more entertaining school year.'
She raised her hand.
Snape's dark eyes found her immediately.
"Beresford. You know the answer?"
"Of course. Powdered root of asphodel mixed into an infusion of wormwood produces the Draught of Living Death, an extraordinarily powerful sleeping potion. Though to be precise, it also requires an infusion of Valerian roots and a Sopophorous bean, the first two ingredients alone are insufficient." She smiled pleasantly. "It is rather cruel, Professor, to open with a trick question on the first day."
Snape returned the smile with a thin, appreciative one of his own.
"Perfect, Beresford. Five points to Slytherin."
"Thank you."
As she had suspected. Snape took every available opportunity to benefit Slytherin, and this was almost certainly the engine behind six consecutive House Cup victories.
Points were stripped mercilessly from every other house; points flowed generously to his own. Other house heads might favour their students occasionally, but none did so with Snape's systematic dedication. McGonagall, by contrast, was notably ruthless about deducting points even from Gryffindors.
"Another question, Potter. Where would you look if I told you to find a bezoar?"
"...I don't know."
"Evidently you didn't think to open a textbook before arriving. Disappointing."
'What a dreadful teacher', Mirabelle thought, genuinely amused.
The first question had been fifth-year content. This one was worse: the wording — "where would you look" — was designed to suggest a geographical answer, which was entirely wrong. Bezoar stones were not found in specific regions. The question could not be answered correctly by thinking about terrain.
She raised her hand. Snape pivoted to her with evident pleasure, ignoring Hermione entirely.
"Beresford. Do you know this one as well?"
"Naturally. Bezoar stones are taken from the stomach of a goat. Despite being called stones, they resemble shrivelled organs. They serve as the primary ingredient in most antidotes." She tilted her head slightly. "Incidentally, Professor, are you often told you have a disagreeable personality?"
"I may have heard that, once or twice." Snape sounded delighted. "Five more points to Slytherin. Though I should note that disrespectful language directed at a teacher will result in deductions in future. Consider yourself warned, Beresford."
Snape continued his methodical assault on Harry's composure without pause.
"Potter. What is the difference between monkshood and wolfsbane?"
Harry looked back at him steadily. "I don't know. Hermione would know, why don't you ask her?"
It was a reasonable observation, and entirely the wrong thing to say.
He had forgotten what Snape had just told Mirabelle: disrespectful language towards a teacher carried a penalty. He had just provided Snape with a reason to use it.
Snape told Hermione to sit down, then turned back to Harry with a slow, unpleasant smile.
"Did you not hear me say that disrespectful language directed at a teacher carries a deduction, Potter? Five points from Gryffindor." He let that sit for a moment, then turned. "Beresford, the answer?"
Mirabelle had not even raised her hand this time. She answered without missing a beat.
"Another trick question. Monkshood and wolfsbane are the same plant, simply referred to by different names. The third name for it is aconite, or, in Muggle botanical terminology, also aconite. The answer to your question is that there is no difference."
"Excellent. Five more points to Slytherin."
They exchanged a look of mutual, faintly conspiratorial satisfaction.
'Quite the scoundrel, aren't you?' — 'Oh, hardly.' That was, more or less, the conversation happening silently between them.
Edith, watching from her seat, looked pained. "That was a genuinely terrible display of teamwork," she said, almost to herself.
"By the way," Snape added, addressing the room, "why is no one taking notes?"
The sound of quills being hurriedly uncapped and parchment being unrolled swept through the classroom simultaneously.
The lesson continued in much the same vein: relentless targeting of Gryffindor, consistent generosity towards Slytherin.
When Snape paired the students to brew a simple Boil Cure Potion, he circulated the room scolding nearly everyone except Draco Malfoy, his evident favourite, and Mirabelle and Edith, whose cauldron was producing exactly what it should.
The most flagrantly unfair moment came when Neville's cauldron went badly wrong, melted entirely, and covered several nearby students in the resulting potion. Harry ended up in the infirmary with boils rising across his body.
Once he was gone, Snape found a reason to deduct points from him anyway. "You were standing nearby. You could have warned him. One point from Gryffindor."
By the end of the lesson, the arithmetic was satisfying. Slytherin was fifteen points higher than it would have been in the history Mirabelle knew. Gryffindor was six points lower, the original deduction had been two.
To reverse the final outcome, she would need to manufacture a gap of twenty-one points or more, and sustain it. This single lesson was a start, not a conclusion. S
he would need to keep widening the margin until Dumbledore would either have to acknowledge the result honestly or tip his hand by overriding it.
'Now then, Dumbledore. Let us see precisely how far you are willing to go.'
Fight fire with fire. If he was going to favour Gryffindor, she would use Snape's corresponding favouritism to match it. She had expected these years to feel like dormancy. They were proving rather more interesting than anticipated.
She was already looking forward to the end-of-year tally.
======
Friday afternoon, no classes.
Mirabelle sat at a table in the Slytherin common room, working steadily through a stack of library books. The pile before her was not inferior in size to Hermione's notoriously large ones, but the content was markedly different. The texts she was reading were sixth and seventh-year level, well beyond the curriculum of any first-year student.
'This seems to be the limit of the general stacks. If I want anything of real use, I will have to access the Restricted Section.'
She had settled on a clear purpose for these four years: a period of quiet preparation and accumulation. Simply attending lessons obediently would not give her what she needed.
She had not come to Hogwarts for the curriculum itself, she had come for the library, specifically its more inaccessible portions, and for the time and space to study independently.
'This spell has room for significant improvement. And its underlying structure is versatile — depending on how it's modified, it could potentially be redirected towards entirely different applications.'
As she read, she organised what she absorbed into structured notes, writing her own analysis alongside the text.
The work involved more than improving existing magic for efficiency; it extended into repurposing spells for functions their original casters had never considered, and from there into the development of entirely original ones.
These were not things a first-year student would ordinarily attempt, and under normal circumstances, no first-year student ever could.
Mirabelle did not think in terms of "ordinary circumstances." She was simply convinced she could do it, and that conviction, steady and unquestioned as breathing, was the foundation of everything she did.
The truly important thing was not the possibility but the certainty. She did not ask whether something could be done. She took it as given that she would do it.
'If applied correctly, the underlying principles here might even allow for the reconstruction of magic drawn from memories of another life. I had underestimated it, assuming the magic from that other world was purely fictional. But it is rather more workable than I expected.'
The magical theory she was building, drawn from the knowledge she had brought with her and the techniques she was now absorbing, had already taken her well beyond anything in the standard texts.
She had drawn on memories of her previous life, on magic that existed only within a story she had once known, and had already constructed several working spells from those foundations.
'The Unforgivable Curses are prohibited. Imperio, Crucio, Avada Kedavra — none of those are usable. But the principle is not the issue. There are other methods of compelling obedience. Fear, for instance, is a perfectly serviceable substitute for the Imperius Curse, and rather more honest about what it is.'
Her left hand turned pages steadily while her right hand moved across her notebook at speed, committing each new line of reasoning to paper before the next one arrived. Her eyes moved between the text and her notes without pause. Under her breath, she murmured fragments of theory, organising her thoughts as they formed.
'Hmm. In principle, this modification should increase Incendio's effective power by approximately ten percent. The degree of control required will increase accordingly, but that will not be a problem.'
When she had exhausted the books in front of her, she gathered the finished ones and carried them back to the library. She was not the sort to simply return books and leave. She selected several new ones, tucked them under her arm, and headed back.
Her interest had already shifted in earnest to the Restricted Section, but it was too early to act on that. Attempting to slip in undetected now would only end in being caught. The ideal opportunity would be a night when the school's attention was entirely elsewhere, when something large enough had happened that no one was watching the corridors.
Halloween, when the troll arrived, seemed the most logical window.
'I can wait until then. The basics will keep me occupied in the meantime.'
The path to ambition was not built in a single step.
For now, she kept her fangs hidden and her claws sharpening. There would be a day that required both.
++++++++
As shown at the end of this episode, Mirabelle develops original magic modelled on knowledge from her previous life. With the exception of the Unforgivable Curses, she generally does not learn new spells where an existing Harry Potter equivalent already exists. Incendio covers fire magic, for instance, so she will not create a separate fire spell from scratch — if she needs something more powerful, she will use an enhanced version such as Incendio Maxima. Conversely, there is no existing lightning magic in the Harry Potter world, so that may be an area where original spells become necessary. The basic principle is: when the story calls for a type of magic and no wizarding world equivalent exists, she will use something original.
Expellianima (Begone, Ghosts)
An original spell used to drive away ghosts and similar entities. It is not, under normal circumstances, used on poltergeists. Note that this is not Mirabelle's own creation, it exists in this world independently. Other witches and wizards are presumably capable of learning and using it.