November Hogwarts was wrapped in a damp, bone-chilling cold. Thin mist rising from the Black Lake lingered all day, and the castle's stone walls were always cold to the touch. Ever since that subtle moment of "standing together" on Halloween night, the relationship between Snape and Lin Yanqing had entered an extremely strange yet remarkably stable new phase.
The Marauders' harassment had not stopped, but their tactics seemed to have changed again. They no longer resorted to petty tricks that could easily leave evidence behind. Instead, they adopted a more suffocating strategy of isolation. Whether in the corridors, the Great Hall, or the library, whenever Snape appeared, an invisible vacuum would instantly form around him, accompanied by deliberately hushed whispers and openly hostile looks. Even some Slytherins, for reasons unknown, had begun keeping a greater distance from him.
Snape's response was to wrap himself in an even thicker layer of ice. As he walked, he was like a black, moving island, his gaze colder than the air outside the castle. Yet under this pressure, his cooperation with Lin Yanqing in the Room of Requirement laboratory became closer and... more efficient than ever.
The laboratory was even messier than usual tonight, but it also resembled a fully functional base more than ever. Besides the central workbench and instrument racks, a small magical temperature-controlled chamber had even been added in one corner, storing several active materials that were extremely sensitive to temperature.
Snape was bent over a complex filtration apparatus made of crystal and mithril, his brow tightly furrowed as he carried out one of the most crucial steps in improving the Wolfsbane Potion—separating and purifying the calming component in the Moonpetal Flower extract while removing the accompanying neurostimulant toxin. The process demanded extraordinarily precise magical control and almost perverse stability. The slightest error would ruin all their prior work and might even contaminate the materials.
Lin Yanqing stood half a step behind and to Snape's side, monitoring the Silverleaf Grass base liquid slowly heating in a nearby cauldron while remaining ready to hand over any auxiliary materials or stabilizers Snape might need. He held his breath, sensing through the contract Snape's extreme concentration and taut mental state, as though he were walking a tightrope high in the air.
The experiment had been underway for two hours, and progress was slow. Fine beads of sweat had appeared on Snape's temple. His wand hand remained as steady as a machine, but his fingertips had turned faintly white.
Suddenly, a dim blue light within the filtration device flickered out of control. An extremely faint yet piercing sound of magical friction came from inside. Snape's arm instantly tensed, and the magical output from his wand tip was forcibly compressed to an even finer degree, but his breathing clearly faltered for a moment.
That momentary disruption caused the edges of the precious liquid in the center of the apparatus, glowing with moonlike radiance, to begin clouding with an ominous haze.
"Stabilizer Number Three, 0.3 grams of ice crystal powder, now!" Snape's voice was hoarse and carried an unquestionable command, along with a trace of urgency born from their previous successful coordination—an urgency even he himself had not noticed.
Almost the moment he finished speaking, a small crystal dish containing the precise amount of ice crystal powder was steadily held out beside him. Lin Yanqing had not hesitated in the slightest.
Using his free left hand, Snape swiftly poured the powder into a specific port on the apparatus. A soft white light flashed, and the agitated magic inside was forcibly soothed. The liquid regained its clarity.
The crisis was over.
Snape did not immediately continue. He remained bent over for several seconds before slowly straightening up. He did not look at Lin Yanqing, but the taut line of his back relaxed slightly.
"Your reaction speed is passable," he said dryly. His voice had returned to its usual coldness, as if that flash of urgency had never existed.
Lin Yanqing said nothing. He silently took the used vessels to the sink and began pre-treating them with a Cleaning Charm. He knew that for Snape, "passable" was practically the same as lavish praise. It was an acknowledgment based on competence, far more fitting for their identity as co-conspirators than any superficial expression of thanks.
Silence descended again, broken only by the hum of the instruments. Not until the core procedure reached a stopping point and Snape carefully sealed away the preliminarily processed essence did the suffocating atmosphere in the laboratory ease slightly.
He walked over to the small table in the corner and picked up the cup that had originally belonged to him—now refilled with hot tea. He took a large sip, then spoke as though mentioning it casually, though his gaze rested on the jars and bottles of dangerous materials on the shelf.
"Lupin," he said. His voice seemed somewhat blurred by the steam rising from the tea. "Flitwick praised him in Charms class this afternoon, said his 'condition has improved.'"
Lin Yanqing's hand paused slightly as he wiped the vessels. He looked at Snape.
Snape's profile was indistinct beneath the dim green light, but in those black eyes glimmered the light of a researcher bordering on fanaticism, along with a trace of... cold understanding.
"A brief calm period before the full moon," Snape said softly, as though analyzing an interesting potion phenomenon. "A disguised 'normality,' meant to conceal the coming 'abnormality.' A very refined... biological instinct."
There was no sympathy for werewolves in his words, only an investigation into the nature of the phenomenon and the excitement of someone about to uncover an answer. He turned to Lin Yanqing, his gaze sharp.
"We need more data. The final live behavioral observation before the full moon is crucial."
This meant that he intended to monitor Lupin more closely—and perhaps more dangerously—on the eve of the full moon. The decision itself foreshadowed enormous risk.
Lin Yanqing felt his heart tighten slightly. He set down the vessel in his hand, walked to the workbench, and pointed at the filtration apparatus that had nearly malfunctioned earlier, as well as the parchment beside it covered in complex data and calculations.
"The magical conduction efficiency at the third node of the apparatus is unstable. It may be due to insufficient mithril purity, or a slight flaw in the Ancient Runes etched inside. Before reaching this step next time, it would be best to conduct a stress test first." His voice was calm as he pulled the topic back to the concrete technical issue before them. Rather than directly responding to that dangerous observation plan, he pointed out the technical root of the earlier risk.
Snape stared at the spot Lin Yanqing had indicated, then looked over the data on the parchment. His brow furrowed again as he sank into thought. After a long while, he finally gave a cold snort. "Obvious. It seems certain so-called 'top-tier alchemical instruments' are nothing more than shoddily made trash."
He did not mention Lupin again, but Lin Yanqing knew he had listened. The warning about the apparatus's hidden danger also applied to that even riskier "live observation" plan—any minor negligence could lead to disastrous consequences.
By the time they left the Room of Requirement, it was already deep into the night. At the cold intersection, Snape turned and left first as usual. But this time, before his figure disappeared, he left behind a brief sentence that drifted over on the wind, almost too faint to hear.
"...Next time, bring your cup."
Lin Yanqing stood frozen in place. Then an indescribable warmth quietly melted the chill of a November night at Hogwarts.
It was not an invitation. Nor was it concern.
It was the confirmation of a basic rule for sharing resources—tea—between co-conspirators. It was the extremely limited... logistical support granted to a reliable ally capable of providing crucial technical assistance during his coming dangerous operation.
Beneath the ice, the warmth was faint, but real. And beyond the castle, the full moon was silently growing rounder and rounder.
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