Frozen Fury and Silent Guardians

The first day of December, Hogwarts awoke to a sudden cold snap. Thick frost bloomed on the windowpanes, and the suits of armor in the corridors seemed even more stiff with cold. The atmosphere within the castle was several degrees colder than the weather.

Snape was back.

He appeared at the dungeon entrance at dawn, silent as a phantom. The hem of his dark robes was damp with dew, his face a near-transparent pale, but his black eyes burned with a suppressed rage and a… near fanatical triumph, enough to ignite the very ice.

He went directly to the Room of Requirement, not even returning to the common room. When Lin Yanqing felt the surging, chaotic, and intense emotional fluctuations through their contract, he immediately dropped everything he was doing and rushed over.

In the laboratory, Snape did not immediately throw himself into work as usual. He stood before the workbench, his back to the door, his shoulders tense. Hearing Lin Yanqing enter, he didn't turn around. Instead, he spoke in a voice that was unusually calm, yet more unsettling than a roar:

"They have a passage," he stated, his voice slicing through the cold air like a knife on glass. "Under the Whomping Willow. On the full moon, Potter, Black, Pettigrew... and Lupin." He emphasized the last name particularly, with undisguised sarcasm and a sense of victory.

He spun around abruptly, his eyes flashing with a cold light, like a viper that had discovered its prey. "I saw him go in, and I saw him come out... that appearance, like a sick wild dog that crawled out of a sewer." The corner of his mouth curled into a cruel arc. "'Recovering'? Heh... just the skin of a human, barely worn before a beast goes hunting."

He didn't explicitly say the word "werewolf," but every syllable was laden with pointed implication. He clenched his fists tightly, his knuckles turning white from the force, clearly struggling to control the immediate impulse to expose and retaliate.

"We need proof," he said, as if speaking to Lin Yanqing, or perhaps convincing himself. "More direct proof. Just seeing them come and go isn't enough... I want to know what's at the other end of that passage! I want everyone to see what kind of... monster the great Gryffindor, Dumbledore's favored students, are sheltering."

His plan was obvious, and even more dangerous—he wanted to enter that passage.

Lin Yanqing's heart sank. He walked to the workbench, not looking at Snape's rage-filled eyes. Instead, he picked up the wolfsbane potion base that Snape had sealed and stabilized the night before, carefully checking its clarity.

"The other end of the passage is, at most, a hiding place," Lin Yanqing's voice was calm, a stark contrast to Snape's agitation. "Considering the Whomping Willow's aggressiveness and method of concealment, that place clearly doesn't welcome visitors. The risk of forcing entry far outweighs the value of any potential 'evidence'."

He put down the crystal vial and finally met Snape's gaze, his eyes holding the pure, detached calm of a researcher. "Our research direction is correct. The potion is preliminarily stable. Rather than risking an almost certain answer to a riddle, it's better to focus our energy on perfecting it. This," he tapped the crystal vial lightly, "is what will truly have an impact."

He was trying to shift Snape's focus from a dangerous act of revenge to relatively safe academic research. He was reminding Snape that they held a more powerful weapon in their hands.

Snape stared intently at him, his chest rising and falling slightly. He understood Lin Yanqing's subtext—don't be impulsive, we have a better way. Rage churned in his eyes; he hated this rational dissuasion, which made him feel underestimated and restrained.

"You think I should just endure it?" His voice was squeezed through his teeth. "Watch them, with that... thing, move freely in the castle? Putting everyone's safety at risk?"

"I think," Lin Yanqing met his gaze, unyielding, "that until we have absolute certainty, tipping them off is the most foolish choice. Unless you are confident you can nail them completely in one go, any rash move will only make them more vigilant, and perhaps even... bite back."

He paused, adding with a subtle reminder, "And don't forget last night. You found them, but are you sure no one else, in the same darkness, found you?"

This sentence was like a bucket of ice water poured over Snape's burning rage. The fervor in his eyes subsided slightly, replaced by a flicker of surprise and a deeper, darker mood. He remembered the feeling of being watched last night; although uncertain, Lin Yanqing's reminder made him unable to ignore the possibility.

"Ding dong! (｀?ω?′) Emergency side quest [Shadow Watch] status update! Potential threat coefficient rising! Please host pay close attention to the contract target's movements, and activate mandatory intervention procedures if necessary!" System Cub popped up with a little elf emoji holding a red warning sign.

Snape fell silent. He shoved Lin Yanqing away abruptly and walked to a shelf in the corner, picking up a bottle containing a liquid as black as ink, bubbling incessantly. It was a magical solvent he had been researching privately, possessing extremely strong corrosive and concealment properties.

"Evidence... I will find it," he murmured, his tone no longer as agitated, but more stubborn and cold. "In my own way."

He didn't say he was going to rush into the passage immediately, but he didn't give up either. He froze his rage, transforming it into deeper scheming. He stopped looking at Lin Yanqing and returned to adjusting the dangerous solvent, as if the previous conversation had never happened.

Lin Yanqing knew his attempt to dissuade had failed. Snape was like a stubborn, provoked young wolf; once he set his mind on something, he wouldn't easily turn back. All he could do now was not to stop him, but to... protect him as much as possible from the shadows, and prepare a retreat and safeguard for his potentially more dangerous actions.

He silently walked to his own workbench and began organizing the seemingly useless trinkets rewarded by the system. His gaze fell on the unused [Concealment Charm]. Perhaps, he needed to prepare more.

The laboratory was once again filled only with the faint sounds of material processing. But this time, the silence was no longer just one of tacit understanding; it was permeated with the tension of an impending storm. Snape was brewing his tempest, and Lin Yanqing began to silently weave him the sturdiest protective net he could.

Outside the window, the December wind howled. Beneath the frozen Hogwarts, undercurrents surged.