Harry had already checked his wand for the third time when sunlight pulled golden lines across the dormitory floor. It was tucked firmly inside his robe.
Ron, wearing a pair of beast-handling gloves so worn they had turned grey, was tiptoeing to drag out his battered leather satchel from under the bed—one he'd bought last year in Knockturn Alley. Inside was a pouch of bug-repelling powder Hagrid had given him. Though he claimed it "smells worse than one of Fred's dungbombs," he still tied the drawstring so tightly it might as well have been guarding Galleons.
At the doorway, Hermione stood with her wand aglow, tracing soft blue light as she cast protective charms on each of them.
Her nose glistened with dewdrops—likely from a recent visit to the kitchen for hot cocoa. The cup now sat forgotten on Ron's nightstand, gone cold.
"Protego Totalum," she murmured. When the blue light brushed over Harry's chest, he felt a thin, invisible film wrap around him like a second skin.
"And this," she added, reaching into her robe and pulling out a small bronze box etched with runes, "is a beast-distracting box I made last night using moonstone and mugwort. Shake it every half-hour. It confuses predators' sense of smell." She shoved it into Ron's hands. "You're in charge of it. Don't lose it."
Ron gave the box a shake, listening to the faint rattle inside. "Merlin, this thing's heavier than Percy's prefect badge." Still, he buried it deep in his satchel like it was a hoard of Galleons.
Harry opened the door to the corridor. A damp wind carrying the scent of pine swept inside.
The Forbidden Forest loomed in the misty distance, its canopy like clumps of dark green clouds. Occasionally, the eerie cry of a Thestral pierced the fog. But it was already morning, and only those who had seen death could see Thestrals—they shouldn't be out.
He inhaled deeply. A hint of decay from last night's nightmare still clung to the back of his throat, as if those black hands were still wrapped around his ankles.
"Let's go," he said, his voice softer than he expected.
At the forest's edge stood a rotting wooden sign, its "No Entry" warning half-devoured by weather and time.
Hermione's wand suddenly flared, illuminating a faint trail below their feet—not so much a path as a trench carved by animal prints and thorn-covered vines.
Ron's gloved hand brushed a leaf slick with slime. He recoiled instantly. "What in Merlin's beard is this sticky stuff?"
"Hellebore sap," Hermione said, crouching down and touching it lightly with a fingertip before bringing it to her nose. "Smells a bit like bitter almonds, but it's not poisonous." A pine needle clung to her hair as she looked up. "Odd, though. Hellebore usually grows on the shaded side. This is the sunny slope..."
Before she could finish, five tiny figures peeked out from behind a tree. Their pointed ears were coated in pine resin, their skin gnarled like tree bark, yet their eyes glowed like fireflies.
All three froze.
Harry's wand burned in his grip. He could still feel the nightmare's touch in his bones, black fingers clenching tight.
"Shhh—" Ron swallowed hard. "Are those... house-elves?"
They were.
The one in front held a half-charred oak leaf, its edges stained dark red.
"Outsiders," it squeaked, voice thin and sharp like wind whistling through an empty bottle. "You come for the bleeding horn?"
Harry stepped forward, wand at his side. "You know about the unicorn? It's hurt?"
The elves pressed their foreheads together, as if sharing thoughts. Then the smallest one suddenly grabbed Harry's robe, its nails nearly tearing through the fabric.
"The blood flows beneath the roots. Black shadows crawl by night. Our trees weep—their roots gnawed away—" It released him suddenly and shrank back behind its companions. "But outsiders should not see. They'll be eaten."
Hermione crouched down, meeting the elf's gaze. "We're here to help. The black shadow—what did it look like?"
"Like fog without a face," another elf whispered. "It wrapped around the unicorn's legs, and the light on its horn vanished." It held up the scorched oak leaf. "Last night, under the full moon, we saw it come from the north. It smelled like rot—"
Crack!
A sudden snap sent the elves fleeing. Only a few oak leaves floated down in their wake.
Goosebumps crawled up Harry's neck. He turned toward the sound. Under a fir tree, barely twenty paces away, a branch thick as a man's arm had been sheared clean off. Dark, viscous fluid clung to the break, and the surrounding grass was blackened and curled, as if scorched by fire and then doused in ice.
Ron nudged a stone with his boot. "That... that's not a Thestral, is it? They don't eat trees."
Hermione knelt beside the broken limb and used her wand to lift a dab of the goo.
Under its glow, the liquid shimmered with an eerie purple-black hue. Up close, it smelled of rust—mingled with rotting roses.
"Unicorn blood is silver," her voice tight, "but according to The Illustrated Guide to Magical Creature Blood, when corrupted by dark magic…" She flipped open Magical Creature Protection and turned quickly to a marked page. "Here—cursed unicorn blood turns purple-black and kills all plants within a five-foot radius within twenty-four hours." She pointed at the scorched grass. "This damage probably happened late last night—matches your dream."
Harry's fingers tightened around his wand.
He could still feel the cold, delicate touch of that unicorn horn from his nightmare.
"So a unicorn really was hurt," he said. "And whatever did it…"
Grrrrrrrgh—
A low, guttural roar echoed from deep within the forest. It sounded like a boulder grinding through mud.
They all went rigid.
It wasn't sharp like a werewolf's howl or screechy like a Thestral. It was deeper. Wet. Like something massive choking on rot.
Ron's fingers twitched over his wand. "I-I think this might be the creature Hagrid mentioned…"
"Retreat," Hermione said abruptly, her voice eerily calm. She grabbed Harry's arm. "Now."
"But—"
"Harry, that sound's at least two miles off, but in the Forbidden Forest, echoes distort. If it's coming toward us, our protection charms won't last ten minutes." Her other hand clutched the beast-distracting box. Her knuckles had gone pale. "And the elf said it came from the north. We're in the southeast. It may not have noticed us yet."
Ron walked backward, wand fixed on the direction of the roar. "I'll bet five Sickles that thing's bigger than an Acromantula—" He tripped on a root and crashed into a bush, brambles tearing at his gloves.
Harry reached out, grabbing Ron's wrist. His skin was icy cold.
"Go," Harry said. His voice was steadier than he felt.
By the time they stumbled out of the forest, the mist had burned off. Sunlight filtered through the clouds, dappled across the lawns.
Hermione's robe was ripped at the hem. Ron had a dead leaf tangled in his hair. Harry's hand was so slick with sweat, it had left marks on his wand.
"I need hot cocoa," Ron gasped, collapsing onto a bench by the Black Lake. "No—ten cups."
Hermione said nothing. She stared at the dark residue on her wand, her brows knitted tight.
"There were traces of dark magic in that slime," she murmured. "I've seen similar markings in Advanced Defensive Spells. Looks like... some kind of corrosive curse."
Harry gazed back toward the forest. The wind carried a faint stink of decay—identical to what he'd smelled in his dreams.
He touched his scar. It pulsed faintly—ever since Voldemort's return, it had been like an invisible thread tugging at his nerves.
But this time felt different—not burning pain. A warning.
"Harry Potter."
The cold voice snapped them around.
Professor Snape stood just three steps away. His black robes billowed in the wind, lips pressed into a tight line beneath his hooked nose.
His eyes swept over Hermione's torn robes, the leaf in Ron's hair, and finally fixed on Harry's face.
"Seems your morning adventure was far more entertaining than Potions class."
Harry's throat tightened.
Snape's office was in the west tower of the castle—he had no reason to be here now.
"Professor, we—"
"Spare me the excuses," Snape cut him off, wand tip nearly poking Harry's nose. "The Forbidden Forest is not your playground. Three second-years were mauled by Redcaps last week. What you encountered..." He paused. Something unreadable flickered behind his eyes. "Was ten times more dangerous."
Hermione stepped forward. "Professor, do you know what's in the forest?"
Snape's eyes flicked toward her as if inspecting a subpar potion ingredient. "Miss Granger, some matters can't be resolved by leafing through books." He stepped back, black robes brushing the grass. "If you wish to survive until final exams, stay out of that forest—especially you, Potter."
As he turned, Harry caught a glimpse of silver ink peeking from his sleeve. A tattoo. It looked like twisted black vines.
It reminded him of the hand from his nightmare, the one buried beneath snow.
"Professor!" he blurted. "If there's real danger in the forest, we should—"
"Silence." Snape's voice struck like an icicle through the air. "You think being the Chosen One exempts you from rules? Come talk to me when you can face a Dementor alone. Until then, stop pretending to be a hero."
With a final glare, Snape turned and strode toward the castle. His shadow stretched long in the sunlight, like a serpent ready to strike.
Ron watched him go, rubbing the arm where a Redcap had once bitten him. "He's more of a soul-sucker than usual today."
Hermione didn't respond. She stared at her wand, still streaked with dark slime.
"That curse residue... it matches something I read in A History of Dark Magic—'Witherbind Curse.' Used by medieval dark wizards to destroy their enemies' lands. It rots plants and congeals blood." Her eyes shone with a strange intensity. "And Snape... he knows something, Harry."
Harry looked back at the forest. Sunlight now filtered through the canopy, and the trees swayed in the breeze, as if beckoning him back.
He touched the wand beneath his school robes. His scar twitched again.
"Tonight after curfew," he said. "We go back—with Hagrid's map."
Ron adjusted his gloves. "This time, I'm bringing extra bug powder."
Hermione flipped open Magical Creature Protection, turning to the unicorn section. "I need to confirm what happens when a unicorn's blood is tainted. And…"
She stopped, looking up at him. "Harry, are you sure?"
Harry remembered the unicorn's eyes from his dream. That cry—it had sounded almost human.
He thought of Trelawney's prophecy: "Rotten roots shall bloom with the flowers of death." He remembered the black vines on Snape's wrist.
"I'm sure," he said, his voice low as wind, but loud enough for his friends to hear. "Some things—only we can stop."
The forest trees rustled in the distance, as if answering.
The wind carried the stench of decay again—sharper this time. And beneath it, the faintest sound, like silver bells breaking—a unicorn's final sigh, just as its horn snapped.