Hermione Granger stopped asking broad questions because broad questions had stopped being useful.
That was the first meaningful difference between her and Harry. Harry confronted what unsettled him. He moved toward discomfort directly, hoping clarity would emerge through moral pressure, through refusal, through some version of straightforward opposition. Hermione did not expect clarity to volunteer itself. If something resisted explanation, she assumed it needed to be observed under controlled conditions. She did not abandon the problem because it behaved strangely. She reduced variables.
That was why Tom found her increasingly interesting.
By now, Hermione had discarded several earlier assumptions. Tom did not help people indiscriminately. He was not simply cold. He was not motivated by praise, because he avoided attention too consistently for that to be credible. He was not building ordinary popularity either, since popularity required emotional labor he clearly had no interest in performing. Whatever he was doing, it was selective, economical, and directional. That much she knew.
What she did not yet know was the rule.
There had to be one.
That belief guided her through the next several days, during which she observed with unusual patience rather than confronting him again immediately. She watched him in class, but not always directly. Sometimes she watched the students around him instead. Sometimes she tracked the timing of his interventions. Sometimes she paid more attention to when he chose not to speak than when he did.
That last category began to matter most.
Tom's silence, Hermione realized, was not absence. It was a form of decision. The pattern of his restraint suggested criteria as surely as the pattern of his interference did. If he corrected one student and ignored another, the difference mattered. If he intervened before one mistake became visible and allowed another to sharpen first, that difference mattered even more.
So she decided to test it.
Not recklessly. Not in a way that would expose her intentions if she was wrong. The experiment had to be small enough to be deniable and precise enough to yield interpretation. In Charms, she arranged the conditions.
A classmate she trusted—one who was willing to participate simply because Hermione had asked, and because she was persuasive enough that very few first-years learned to refuse her without preparation—agreed to make a visible but harmless mistake within Tom's hearing. Nothing severe, nothing that would invite professor intervention before anyone else could react. Just enough to create an opening.
Hermione positioned herself two rows away.
Flitwick's instructions began. Wands moved. Feathers trembled and lifted in uneven increments around the room. At the right moment, the student made the planned error—too much emphasis in the motion, the incantation clipped incorrectly at the end. It was obvious enough to be noticed by anyone paying attention.
Tom did not speak.
Hermione's pulse tightened slightly, though her expression remained carefully neutral. She watched him from the edge of her vision. He had noticed. She was certain of that. His attention had flicked toward the mistake and then away again. But he let it pass.
Interesting.
The first data point by itself meant very little, but it mattered that the non-intervention had been clean. Tom had not hesitated, nearly corrected, or half-engaged. He had made a decision quickly and without visible conflict.
Later in the same lesson, a second opportunity emerged naturally, and it was better than the first because Hermione had not arranged it. Another student—this one competent but flustered, not the sort to ask for help unless failure became undeniable—misjudged a smaller, more private element of the task. The error was not visible to the class. It was the kind of mistake that lived on the edge of embarrassment without crossing fully into it.
Tom corrected that one immediately.
Softly enough that only the student heard.
The reaction was equally quiet, but Hermione saw it: the quick stillness, the adjustment, the improvement that followed almost at once. More importantly, she saw the student's expression afterward—not grateful, not exactly. Sharpened. More aware.
By lunch, Hermione had already drawn the outline of the rule.
He did not help people who expected help.
He helped people who would be altered by it.
The distinction was subtle enough that most people would never have bothered making it. Hermione could not stop making it. The students Tom selected were almost always in a particular state: competent enough to use the correction, unsettled enough to be changed by receiving it, proud enough that they would not have sought help first, and impressionable enough that the exchange would affect more than immediate performance. He was not simply improving outcomes. He was choosing the kinds of minds that absorbed intervention into identity.
When she explained it to Harry at lunch, she did so in the quick, compressed way she used when she was thinking faster than speech could comfortably support.
"So he doesn't want the ones already waiting for help," she said. "That's too easy. It doesn't tell him anything. He chooses the ones who'll move because of it."
Harry frowned at once. "Move how?"
Hermione shook her head. "That depends on the person. That's the point. It isn't one result. It's a shift."
Ron, predictably, looked between them with mounting irritation. "You're both acting like he's some sort of scientist with mice."
Hermione did not answer immediately, which told Harry more than a direct answer would have. Ron saw it too and sat up slightly.
"You can't be serious."
"I'm saying," Hermione replied carefully, "that he wants to know what happens when you change the right thing at the right moment."
Harry's expression darkened. "That's worse."
"Yes," Hermione said. "It is."
The difficulty, however, was that identifying the rule did not resolve the larger problem. It only made the shape of it clearer. Hermione knew now that Tom selected for response, but selection itself could still serve many ends. Curiosity. Control. Efficiency. The construction of dependence. The distribution of pressure. Perhaps all of them. She needed another answer.
She confronted him again in the library because the library remained the best place for truthful conversation of a certain sort. It rewarded quiet, discouraged spectacle, and gave people too much time to think between sentences. Tom seemed to prefer it for similar reasons.
He was seated at the same general table as before, though not in exactly the same place. Hermione noticed that immediately. He altered position enough to prevent routine without sacrificing utility. It was a small detail, but she had begun collecting small details because every one of them tended to mean something with him.
"You choose people who can be adjusted," she said, without greeting or preamble.
Tom looked up from his book, his expression composed. "That sounds scientific."
"It's accurate."
He let the silence stretch for a moment, then closed the book with measured care. "And if it is?"
She sat down this time without asking. That, too, was intentional. She would not let the interaction organize itself around his comfort.
"Then you're doing it on purpose."
"Yes."
The admission landed even harder because it came so easily. Hermione had expected resistance at least long enough to establish the terms of the exchange. Instead, Tom accepted the core charge instantly, forcing her to move to the next question without the stabilizing comfort of debate.
"For what?" she asked.
His answer came almost at once.
"To see how little is required."
The sentence chilled her in a way she could not entirely conceal.
"Required for what?"
Tom held her gaze. "Change."
Hermione felt the answer settle into the conversation like something cold poured into clear water. It spread without noise, altering everything around it. There was nothing theatrical in what he had said. No cruelty for its own sake. No boast. That was exactly what made it so wrong. He sounded clinical. He sounded as though he were discussing structure rather than people.
She leaned forward slightly, lowering her voice without planning to. "You're experimenting on them."
Tom's expression altered by less than a fraction. "That word implies a lack of consent you cannot prove."
Hermione stared at him. "They don't know what you're doing."
"Most people don't know what anyone is doing to them," he said. "That has never prevented the result."
She was quiet after that, but not because she lacked a response. She had too many. Moral outrage, analytical curiosity, disbelief, the urge to walk away, the stronger urge to keep him talking—all of them moved through her at once, and none of them seemed sufficient. Tom had an infuriating ability to turn every objection outward, away from his own singularity and toward general truths ugly enough to be difficult to deny. It was not that he defended himself well in the usual sense. It was that he dissolved the uniqueness of his behavior by embedding it in wider human tendencies.
That was a defense more dangerous than lying.
"You think that makes it acceptable?" she asked.
"No," Tom said.
The answer caught her off guard.
"No?"
"I think acceptability is a very limited category."
That was one of the worst things he had said to her so far, not because it was dramatic, but because it revealed so much about the internal scale on which he operated. Most people arranged action first around whether it was permissible, kind, fair, deserved, cruel. Tom seemed to sort those judgments into a secondary category—real, perhaps, but not primary. Something else came first. Efficiency. Accuracy. Structural truth. She wasn't sure yet.
He watched her thinking. She disliked that most of all. With Harry, silence usually meant feeling. With Tom, silence meant observation.
Hermione changed direction again. "Why tell me any of this?"
Tom considered that for a moment. "Because you asked correctly."
"That isn't an answer."
"It is," he said. "You just dislike the reason."
She sat back, suddenly aware that she had crossed another threshold. Tom was no longer merely evading or destabilizing. He was rewarding precision with partial truth. That meant he found the conversation useful too. The realization made her colder than anything else had.
When she left the library, she did not immediately go to Harry. She walked first, letting the castle's corridors absorb some of the force of the exchange. It would have been easy to tell him everything. He would have listened. He would have believed her more readily now than before. But speech made things real in a particular way, and Hermione was not yet ready to give those sentences that kind of permanence.
That night, when she finally did speak to Harry in the common room, she edited without quite meaning to. She told him Tom had admitted choosing people deliberately. She told him that the selections were based on how little input produced a shift. She told him that he viewed attention and pressure as variables. But she did not repeat every sentence. Not the part about acceptability. Not the part about experiment and consent. Those remained lodged in her privately, not because she wanted to protect Tom, but because saying them aloud would make the scale of him harder to ignore.
Harry listened in full silence.
When she finished, he stared into the fire for a long time before saying, "So he's not just doing things because he can."
"No," Hermione replied. "He's measuring."
Harry's expression hardened. "That's worse."
"Yes," she said again. "It is."
Across the castle, Tom sat in the Slytherin common room, where the atmosphere around him had changed in ways subtle enough that only careful observation could separate them from ordinary school drift. A second-year had begun pausing before speaking whenever Tom was nearby, not from fear but from increased self-awareness. A first-year who had been corrected twice now sought opportunities to be within earshot without making the desire obvious. Nott had become less invisible, though not louder; he simply occupied silence more intentionally than before.
Tom observed all of it without apparent reaction.
In the dormitory later, after the others had settled, Nott spoke quietly into the darkness.
"Granger knows more."
Tom kept his eyes closed. "Yes."
"Does that matter?"
"Eventually."
There was a pause. "Shouldn't it matter now?"
Tom opened his eyes to the dark ceiling. Hermione mattered because she asked better questions than Harry and because she was increasingly close to understanding the method even if she still could not see the destination. But understanding the method was not the same as stopping it. In some cases, it made people more useful.
"Only if she decides clarity is more important than accuracy," Tom said.
Nott did not understand the sentence fully. Tom knew that from the silence that followed. But he understood enough to ask no more.
Tom closed his eyes again and reviewed the sequence of the day. Hermione had confirmed what he already suspected: she was the first genuine intellectual pressure point at Hogwarts. Dumbledore watched. Harry objected. Draco aligned. Nott absorbed. Hermione investigated.
Good.
Investigation, properly managed, had uses.
She still believed exposure weakened hidden structures. She still believed that once enough of the pattern was named, resistance would become easier. That belief was common among intelligent people. It was also often wrong.
Sometimes knowledge destabilized a system.
Sometimes it merely gave the system better-defined edges.