HP: Those Years Sleeping with the Half-Blood Prince

Severus's face remained expressionless. He simply used the tip of his wand to carefully pick up a little of the failed potion, brought it close to his nose at a safe distance, and then observed its color and texture.

"The porcupine quills were added too early, and they reacted with the incompletely mixed snake fang powder at the wrong temperature," he stated calmly. "This pot is ruined. Clean it up and start over."

"Start over? There might not be enough time..." Ian glanced at the hourglass.

"That's enough." Severus had already begun cleaning the crucible, his movements incredibly fast. "Do as I say, without making a single mistake."

Meanwhile, Sirius and James also ran into trouble.

They seemed to have gotten the order of the porcupine quills wrong, and only tried to salvage the situation after adding the pufferfish eyes. As a result, a plume of black smoke rose from the crucible. Although it didn't explode, the liquid turned a strange dark green and had a pungent smell.

Professor Slughorn strolled over, his round face slightly sullen with a smile, but he still said encouragingly, "Hmm... very creative, but there's still a long way to go, children. Two points deducted from Gryffindor for a dangerous sequence error. Perhaps you should pay more attention to the blackboard than to your neighbors' progress?"

The two shut up in frustration, trying to salvage the situation, but it was clearly too late.

In another corner of the classroom, Aris was meticulously following the textbook and the blackboard, performing each step with unwavering precision. His movements were slow but extremely accurate, as if he were executing a complex mathematical formula.

Kevin, who was beside him, only needed to occasionally hand him some materials, and the potion steadily changed towards the standard light blue color described in the textbook in his hand.

As Professor Slughorn passed by, he exclaimed happily, "Excellent, Mr. Thorne! Slytherin, five points!"

Severus's second attempt began.

He took over most of the key operations, but he gave clear instructions at every step and let Ian do the supporting work.

"Keep the fire low. Now, add the snake tooth powder in three batches, five seconds apart, using a silver spoon. Do not pour it in directly."

"Stir, counterclockwise, slowly, at a constant speed...stop."

"Slug, now, push it in with the tip of the silver knife, being careful not to touch the side of the pot."

"Two porcupine quills, thrown in simultaneously and vertically, neither too early nor too late."

His voice was steady and emotionless, yet it possessed a power that compelled people to believe and follow him.

Ian was completely focused, not daring to be distracted in the slightest, and strictly followed Severus's instructions, like the most diligent apprentice.

Finally, as the sand in the hourglass was about to run out, the liquid in the cauldron in front of them turned a pale blue color that was almost clear.

Although the broth in Biarris's pot was a bit cloudy and didn't produce the pearly luster described in textbooks, but rather just some ordinary steam rising from it, it at least looked the part.

Professor Slughorn strolled over again, scooped up a little with a long-handled spoon, examined the color carefully, and then gently smelled it.

"Hmm..." He pondered, his eyes shifting between Severus's calm, expressionless face and Ian's tense look. "The color is basically correct, the texture... is acceptable, and the smell is up to standard. Considering this is the second attempt, and given the limited time..."

He paused, then smiled. "Barely acceptable, Mr. Burke, and, Mr. Snape..."

He turned to Severus, his tone noticeably warmer, "Excellent on-the-spot instruction and solid fundamentals. I can see that you have an understanding of the steps that goes beyond the textbook. Slytherin, ten points for successful remediation and clear teaching thinking."

Severus merely nodded slightly, showing no sign of joy.

Ian let out a long sigh of relief, feeling a thin layer of sweat on his back.

The bell rang, signaling the end of get out of class.

The students began packing up their things, and the classroom was filled with sighs of relief and conversations that were either excited or frustrated.

"Let's go," Severus said swiftly as he bottled and labeled their finished product. "Next time, watch the steps three times yourself first."

"Yes, Master Potions," Ian replied with a smile, this time a much more genuine one.

He glanced at the bottle of "barely adequate" potion, then at Severus's expressionless profile, and a quiet unease stirred within him.

……

After Potions class, the days seemed to be under a constant speed spell, slipping by one by one.

The Hogwarts castle gradually transformed from a novel and fantastical backdrop into a detailed and everyday scene.

Ian figured out the fastest route from the cellar to the Great Hall that wouldn't be spotted by Filch; he knew roughly what time the house-elves would refresh the leftover pudding plates left by the kitchen door; and he got used to watching through his dormitory window as the giant squid's tentacles occasionally lazily brushed against the glass, casting swaying shadows.

He still excelled in Charms class, and Professor Flitwick had twice praised his precision in hand gestures during class. Transfiguration class was a bit more difficult, but compared to Potions class, it was a piece of cake.

Despite Severus's meticulous "instructions"—"Three and a quarter turns counterclockwise, at a steady pace, don't stop," "Put the porcupine quills out now, right now, don't wait," "Get away, it's going to smoke"—Ian still manages to create an unexpected surprise at some point.

Either the stirring stick slipped out of my hand and fell into the pot, or I grabbed the wrong ingredient bottle ("Moonstone powder and pearl powder look exactly the same!").

Whenever this happened, Severus would always make amends with astonishing speed, his face as black as the bottom of a cauldron, but his hand movements were steady and precise.

Afterwards, he would use a flat tone to break down Ian's mistakes clearly, down to the point of "your wrist tilted five degrees more in the third second," leaving Ian speechless and forced to admit defeat. Then, Ian would continue to make new and creative mistakes in the next operation.

Ian noticed that some of the textbooks Severus had picked up from secondhand bookstores had badly worn edges and pages that showed signs of careful repair.

His small bag containing potion ingredients was made of faded old cloth, and the several glass bottles were of different styles, clearly put together from various sources.

Severus was exceptionally frugal in his handling of materials. When scraping powder, he would scrape off three more layers from the inside of the mortar. When cutting snake fangs, he would cut at an angle accurate to the millimeter, striving not to waste a single bit.

This reminded Ian of Severus counting coins in the Diagon Alley used bookstore.

It was early morning, the third weekend after Potions class.

Severus got up early again and sat in the corner of the common room by the window, previewing next week's new chapter of "Potions and Magical Elixirs" by the light of the fireplace and the faint light filtering through the lake outside.

He watched intently, taking notes with a quill pen on the old parchment, his handwriting small and dense.

This is what Ian saw as he walked out of the dormitory corridor with a yawn. He rubbed his eyes, didn't disturb him, and turned back to his dormitory.

When Ian returned from the auditorium at noon, there was a small package at the foot of his bed.

Kevin leaned closer curiously: "What's this? Did your family send it?"

"Just a little something," Ian mumbled, quickly stuffing the package into the bottom of his bedside table.

In the afternoon, Severus went to the library as usual.

Ian then slipped away to the owl's hut and mailed a letter.