HP: Those Years Sleeping with the Half-Blood Prince

Kevin, who was listening nearby, couldn't help but chuckle, earning a glare from Ian.

Aris added objectively, "If Ian fails this course, his entire academic year will be dragged down, and it might even affect his subsequent electives and NEWT..."

"Aris, that's a good summary. You don't need to summarize next time..." Ian interrupted him listlessly.

Severus finished the last bite of peas, wiped his mouth with a napkin, and remained silent for a few seconds. Just when Ian thought he was about to be silently rejected again, he heard Severus's flat voice:

"Tonight, in the Room of Requirement, bring your textbooks, notes, and that paper from last week about the boil treatment solution—if you wrote it."

Ian's eyes lit up. "I wrote it! It might not be quite right... but it's definitely written! Tonight, right? No problem! You're so great, Severus!"

He was so happy he almost patted Severus on the back, but under the other's gaze, he patted his own thigh instead.

So, before curfew that night, the reading corner of the Room of Requirement became a temporary "potion emergency station".

Ian opened his potions textbook, which was covered with all sorts of questionable doodles and folded corners, along with several notes with messy handwriting and mottled ink.

Severus sat opposite him, with only a clean textbook, a quill pen, and a blank parchment in front of him.

His expression remained as blank as ever, but his brow twitched noticeably when his gaze fell on Ian's "masterpieces".

"Where to begin?" Ian tried to sit up straight, adopting the posture of a good student.

"Basics," Severus said succinctly, pointing to the first chapter of the textbook with the tip of his quill. "Tell me, before handling porcupine quills, why must a small copper knife be used, and why must silver utensils be kept out of contact for more than three seconds?"

"Uh... because some component in porcupine quills reacts with silver hair in some kind of... reaction? causing the quills to become brittle or ineffective?" Ian tried to recall.

"Wrong." Severus explained the principle in a calm voice, and pointed out precisely which page and paragraph in the textbook it came from.

Ian: "..." He quickly flipped to the third page and, sure enough, found the relevant description among the densely packed small print. "Who can even see this?!"

"To pass, you have to see it." Severus remained unmoved. "Next, in the standard recipe for the Water of Life and Death, why must the drowsy bean juice be stirred three times clockwise and then once counterclockwise after adding the aconite extract, then left to stand for ten seconds before continuing?"

For the next hour or so, Ian felt as if he had been thrown into a drum made up of countless tiny bits of knowledge, and was being crushed by Severus’s calm yet cruelly precise questions.

For the first time, he realized with such clarity how many details he had missed in class. In Severus's eyes, Potions was a precise world constructed from countless rigorous rules and delicate balances, allowing no room for "probability," "possibility," or "whims."

"Stop...stop for a second..." Ian rubbed his throbbing temples, feeling like his brain was on fire. "Let me catch my breath, Severus, knowledge isn't getting into my brain..."

Severus glanced at him, said nothing, but put down his quill and took a sip of the now-cold mint water beside him.

Ian slumped back in his chair and lamented, "Merlin, I used to think potions were just a matter of following a recipe, mixing and boiling... How come with you, it's harder than solving an ancient rune riddle?"

"Potions aren't cooking." Severus put down his cup, his voice still calm, but perhaps because of the quiet of the night, or perhaps because of Ian's miserable state, his calmness seemed to lack some of his usual coldness.

"Every step has a reason, every material has a life and a temper; ignore them, and they will take their revenge on you in the crucible."

He glanced at Ian's paper on boil treatment, which he had circled in red ink several alarming errors.

"For example, you might think that 'armadillo bile' can replace 'African tree snake skin powder' in equal amounts to enhance the suppuration effect—if you actually do that, the person who drinks the medicine will not experience swelling reduction, but will instead develop a whole body covered in boil-like purple rashes that are incredibly itchy and last for a week."

Ian: "...I'm sorry, I was wrong." He touched his arm, still shaken.

After a while, Ian perked up again and pointed to another spot in his notebook: "What about this? Why does the antidote for the swelling potion require grinding dried fern leaves with moonstone powder instead of mixing them directly? I always felt it was unnecessary..."

Severus's gaze fell on the question, and a hint of something like "finally, a question with some merit" seemed to flash in his dark eyes.

He picked up a quill pen and quickly drew a simple diagram on a blank piece of parchment, then began to explain.

His voice was not loud, his pace was steady, but his word choice was precise. Those tedious and complicated steps and principles seemed to become clear and orderly under his detailed explanation.

At first, Ian forced himself to listen, but gradually he was able to follow the train of thought and occasionally even ask a question or two.

Finally, when the clock struck eleven, Severus closed his textbook.

"That's all for tonight." He packed his things. "I'll go through the basic principles from Chapters 6 to 8, check them tomorrow night, and do the practical exercises... This weekend, I'll start redoing the simplest boil treatment solution here."

Ian let out a long sigh of relief, feeling completely drained, but his mind was now filled with something tangible, no longer a chaotic mess of anxiety.

"Understood, Master," he replied weakly, then, as if remembering something, added, "Thanks, Severus, really."

Severus grunted, stood up, took two steps, then stopped. Without turning around, he floated over in a low voice: "...The second example in the third paragraph of the paper is wrong. You should refer to page 211 of 'Potions and Magical Elixirs,' not page 198."

Ian paused for a moment, then quickly flipped through his paper and found the error. "...Oh."

Watching Severus's straight but slightly thin figure disappear through the door of the Requirement Room, Ian rubbed his face and couldn't help but chuckle softly.

Okay, although the process was as painful as being choked by Grindelwald and forced to drink medicine, it didn't seem that bad.

In the following weeks, this kind of "tutoring" became the norm.

The air in the Room of Requirement is often filled with the bitter smell of herbs, occasionally mixed with the strange smell from one of Ian's operational mistakes, and Severus's concise and stern corrections.