The room grew impossibly cold. Min-Jae could see his breath as he stared into the glowing mirror. The ghost girl's eyes locked with his through the glass — empty, sunken, but filled with a strange recognition.
"You… came back," she whispered. Her voice was like the rustling of dry leaves, distant yet chilling.
"I don't even know you," Min-Jae said, but his voice trembled.
"Yes, you do." She tilted her head, smile cracking wider. "You promised me."
Min-Jae stepped back. "What are you talking about?"
Yejin grabbed his arm. "Min-Jae, don't talk to her. It's not safe."
But he couldn't look away. Something in the girl's face stirred a faint memory. A dream he'd had as a child. A dark corridor. A broken promise.
Ha-Neul shouted, "We need to break the mirror! That's how we end this!"
He picked up a chair and swung it. But just before the impact, the girl screamed — not with fear, but with fury. The mirror absorbed the blow like water. The glass rippled, and the chair passed through — then vanished.
"Ha-Neul!" Min-Jae shouted. "Where did it go?!"
The mirror's surface shifted again, and suddenly, Ha-Neul was on the other side. They could see him — trapped in that ghostly classroom, banging on the inside of the glass.
"No! No! Get me out of here!"
Min-Jae rushed forward, but the glass was solid again. Cold. Ha-Neul's fists pounded from the inside, but no sound came through.
"We have to pull him out!" Yejin cried.
The ghost girl laughed softly. "One by one, you'll all come in. Like before."
Min-Jae spun toward her. "Before? What do you mean?"
Her eyes burned now, a faint red glow swirling in the black. "You broke the circle. You ran away."
Suddenly, the lights went out. The room plunged into darkness.
Min-Jae turned on his flashlight. The beam flickered, then steadied. But Ha-Neul was no longer in the mirror. Instead, the surface showed a forest — twisted trees, shadows dancing between them, and the faint outline of a door in the distance.
"That door…" Yejin whispered. "It looks like the one from the basement."
Min-Jae nodded. "The locked door."
The ghost girl's voice echoed once more:"If you want to save him… open the door."
Then the mirror cracked. A thin, spidery fracture ran from top to bottom — and vanished. The glow faded. The girl was gone.
Min-Jae and Yejin stood in silence.
"I'm going to the basement," Min-Jae said, jaw clenched. "I don't care what's down there."
Yejin didn't argue. She simply nodded and followed.
They descended the stairs, each step creaking louder than the last. The air grew damper, heavier. At the bottom, the basement door waited — old, splintered wood covered in strange symbols. This was the door from the mirror. No doubt.
"Do you think she's behind it?" Yejin asked.
Min-Jae nodded slowly. "Or what's left of her."
He reached out, turned the rusted handle, and pushed. The door opened with a long groan.
Inside was complete darkness.
They entered.
The room was empty… at first. But in the far corner, a faint glow shimmered. Another mirror stood there — much older, cracked along the edges. And in it, Ha-Neul sat curled up, clutching his knees, whispering something.
"Ha-Neul!" Yejin called.
He looked up, eyes wild. "She won't let me go. You have to finish it."
"Finish what?"
Ha-Neul pointed at the floor. Symbols had been carved into the concrete, forming a circle. Candles — long melted — sat at five points. A ritual circle.
Min-Jae's eyes widened. "This… this is a sealing spell."
"She was trapped here," Ha-Neul whispered. "But someone broke the circle. That's how she got out."
Min-Jae stared at the missing symbol. One part of the circle was smudged, destroyed. He remembered now — as a child, sneaking into this very school. Finding the circle. Thinking it was just a game. He'd erased part of it with a stick.
"You did this," the girl's voice said softly behind him.
Min-Jae spun around. She stood there. No longer a shadow — now fully visible. Pale. Thin. Eyes glowing red.
"You set me free," she said. "Now you finish what you started."
Yejin stepped in front of Min-Jae. "He was just a child."
The girl's expression didn't change. "A promise is still a promise."
Min-Jae looked at the chalk in his hand — where had it come from? His fingers trembled. Slowly, he stepped into the circle and began redrawing the missing symbol.
The girl's form began to flicker.
"No!" she hissed. "You can't —"
Min-Jae finished the final stroke.
The room exploded in white light. The mirror shattered. The girl screamed — a shriek that cut through the walls, the ceiling, the air itself.
And then…
Silence.