Carlos and Lando had the map fragment laid out between them on the table, their wands illuminating the faded parchment. Both boys were growing increasingly frustrated.

"This thing has to do something," Carlos muttered, his voice tinged with irritation. He drummed his fingers on the desk, staring at the cryptic lines and faint symbols that seemed to mock their efforts.

"Maybe it's more about timing than spells," Lando suggested, though his tone carried doubt. He'd lost track of how many charms they had tried.

Carlos groaned. "Or maybe we're just idiotas missing something obvious." He raised his wand and cast a revealing charm for what felt like the hundredth time. "Aparecium."

To their shock, the map pulsed faintly, the faded lines sharpening as new symbols emerged. One in particular began to glow with an ominous, dark hue.

"Did you see that?" Lando exclaimed, leaning in closer, his voice rising in excitement.

"Sí," Carlos answered, his stomach twisting uneasily. He pointed to a newly appearing sigil, pulsing faintly near the outline of the lake. "That wasn't there before."

Lando nodded. "This could be it, Carlos. This could be the next clue."

"Or it could be a warning," Carlos frowned, his expression grim.

"Either way, we need to check it out." Lando was already reaching for his coat, his excitement outweighing his caution.

Carlos hesitated, glancing at the dark sigil. Something about it made his skin crawl. He felt as though he had seen it before. "Fine," he said finally, grabbing his cloak. "But if this turns out to be a bad idea, I'm blaming you."

The air was cold and biting as they made their way to the lake, the moonlight cast a silvery glow over the still water, but something about the scene felt off. The usual peacefulness of the area was replaced with an oppressive silence, and a faint hum seemed to resonate through the ground as they approached.

"Does it feel colder to you?" Lando asked, his voice breaking the eerie quiet.

"It's more than that," Carlos replied, his voice tight. "It feels... wrong."

As they reached the edge of the lake, the glowing sigil from the map became visible, etched into the frost that covered the rocks. The lines were jagged and precise, and the magic emanating from them was palpable- a heavy, dense force that made it hard to breathe.

"It's here," Lando whispered, pointing to the frost patterns.

Carlos knelt to get a closer look. "Stay back," he warned, but his curiosity overruled his caution. He reached out, brushing his fingers against the frost.

The effect was immediate. A searing pain shot up his arm, and he yanked it back with a sharp cry. His veins darkened, the shadowy magic crawling up his skin like ink spreading through water.

"Carlos!" Lando grabbed him, his voice laced with panic. "What's happening?"

"It's the rocks," he gasped, clutching his arm. The pain was excruciating, but worse was the feeling of something dark and invasive, like the magic was trying to consume him.

"We need to get out of here," Lando said urgently, pulling Carlos back.

Before they could retreat, the frost on the ground began to spread rapidly, forming a jagged circle around them. The faint hum turned into a low, menacing growl, and shadows began to coalesce within the frost patterns.

"Get back," Carlos yelled, his voice strained. He pushed Lando behind him, his wand raised despite the pain coursing through his arm.

"I'm not leaving you," Lando argued, his own wand at the ready.

The shadows took shape, forming a monstrous, serpentine figure with glowing eyes. It lunged at them with a deafening roar, forcing both boys to dive to the side. "Confringo!" Lando shouted, sending an explosion of light toward the creature. It recoiled but didn't disappear, its form shifting and reforming as if fueled by the very magic in the air.

Carlos gritted his teeth, raising his wand despite his trembling arm. "Stupefy!" The spell hit the creature, but it only staggered, its glowing eyes narrowing as it turned on him.

The fight was chaotic, their spells lighting up the night as they struggled to fend off the creature. It wasn't until Carlos managed to cast a powerful banishing charm that the entity finally retreated, dissolving back into the frost.

They stumbled back toward the castle, Carlos' condition worsening with every step. His veins remained darkened, and his breathing was labored. He looked down and to his horror he could see the faint werewolf scars on his arms getting darker, more prominent. The Glamour charm was wearing off, fast.

"We have to get you to the hospital wing," Lando said, his voice tight with worry.

"No," Carlos protested weakly. " Pomfrey will ask too many questions."

"Then we're going to Alonso," Lando said firmly.

Carlos didn't argue this time, too weak to protest.

Fernando was in his office, pouring over old texts when the boys burst in. He looked up, startled by their disheveled appearance.

"Merlin's beard, what happened?" He rose to his feet and rushed over to them.

"Dark magic," Lando replied quickly, guiding Carlos to a chair. "We were at the lake, and something attacked us. He touched the frost-"

Fernando's expression darkened. "You shouldn't have gone there alone."

"We didn't know it was that dangerous," Carlos said, his voice hoarse.

Fernando knelt beside him, gently rolling up the cuff of his sleeve before stopping, seeing the scars. He mentally cast a fresh Glamour Charm and waited a couple seconds as the effects took place, unknown to Lando. His jaw tightened as he saw the darkened veins. "This magic is ancient and powerful. You're lucky to be alive."

"Can you fix it?" Lando asked, his voice desperate.

"I can try," Fernando said, pulling out his wand. He muttered a series of complex incantations, and a faint light surrounded Carlos' arm. The dark veins began to recede slowly, though not completely.

"This is a temporary fix," he said grimly. "The magic is still in you. It will take time to fully remove."

Carlos leaned back in the chair, exhausted but grateful. "Gracias, Nando."

Fernando sighed. "You two need to be more careful. The Chamber of Shadows is not something to take lightly. If you continue down this path, you must be prepared for the dangers that come with it."

"We are," Lando said firmly, glancing at Carlos. "Right?"

He nodded, though his expression was weary. "We have to be."