Lin Ze sat beside Grandmother on the edge of the bed, the red key still warm in his palm. The shattered vase lay between them like evidence of a crime neither had meant to commit.
Grandmother's gaze lingered on the key, then drifted to the window where late-morning light filtered through dusty curtains.
"Your grandfather never liked talking about those years," she said quietly. "When he finally quit being a private investigator, he told everyone—including me at first—that it was for practical reasons. Better pay in engineering, regular hours, a future he could build with his own hands. But that wasn't the whole truth."
She folded her hands in her lap, knuckles pale.
"The everyday cases wore him down. Not the dramatic ones you see in films—no international spies or masked killers. Just ordinary people, day after day, revealing how ugly they could be to one another. A wife paying him to prove her husband's affair, knowing full well it would destroy their children's home. A son hiring him to find his missing father, only to learn the father had fled debts the son himself had secretly run up. Business partners accusing each other of theft, when both were stealing in different ways."
Grandmother's voice grew softer, as if speaking too loudly might summon those memories into the room.
"He used to come home late, sit at the kitchen table, and stare into his tea for hours. Said he had seen too much of human nature stripped bare. Greed dressed as practicality. Betrayal disguised as love. Cruelty justified as survival. Every file he closed felt like adding another brick to a wall between him and the rest of the world. After a while, he couldn't bear it anymore. He wanted to create things—bridges, buildings, something solid and honest—instead of tearing open people's lives to expose the rot inside."
Lin Ze listened, the key heavy in his hand. He had expected tales of supernatural terror to explain the locked box, not this slow, corrosive disillusionment.
"So the cases in the box…" he began.
Grandmother nodded. "The ones he could never close. Not because they were too complex or dangerous in the physical sense. Some lacked evidence. Some clients suddenly withdrew. A few… the truth was simply too ugly, and revealing it would have destroyed innocent lives without bringing justice. He carried them like scars. When he finally locked the box, he told me it wasn't to protect the world from the cases. It was to protect himself from remembering how little goodness he'd found in people."
She looked at Lin Ze earnestly. "They're just unsolved files, Ah Ze. Paper and photographs and painful truths. Nothing supernatural. Nothing worth reopening old wounds for."
Lin Ze turned the key over, tracing the crimson coating with his thumb. Grandmother's explanation made sense—perfect, human sense. And yet…
"If they're only ordinary unsolved cases," he said slowly, "then why lock them away so dramatically? Why hide the key inside a vase? If they were just reminders of human ugliness, Grandfather could have burned them. Or left them in a drawer. But he buried the box deep in the attic and hid the only key in something fragile, something he'd never risk breaking in life."
He met her eyes. "That doesn't sound like a man protecting himself from bad memories. That sounds like a man afraid something might still happen if those files saw the light again. Unsolved cases don't stay unsolved by accident. There's always a reason—someone powerful covering tracks, evidence that disappeared too conveniently, witnesses who changed stories overnight. If Grandfather couldn't close them, maybe there was a bigger truth he got too close to. Something worth hiding."
Grandmother opened her mouth to protest, but Lin Ze pressed gently on.
"I'm not a child anymore, Grandma. I'm twenty-three. I work with facts and evidence every day—structural loads, material stress points, failure analysis. Let me look. If it's just painful human stories, I'll close the box again and we'll forget it. But if there's more… maybe I can finish what Grandfather couldn't."
She studied him for a long moment, worry deepening the lines around her eyes.
"You have his stubbornness," she said finally. "And his curiosity. That's what frightened me most."
Silence stretched between them.
At last Grandmother sighed, a sound of surrender. "Very well. You may open the box. But on two conditions."
Lin Ze waited.
"First, nothing leaves the attic. Whatever is inside stays inside. No taking files home, no photographs, no notes. Read them there, under that roof, and leave them be."
He nodded.
"Second," she continued, voice trembling, "if you feel yourself being pulled in—if the cases start following you home in your thoughts, if you dream of them, if you feel watched—promise me you'll stop. Seal the box again and walk away. Some truths aren't worth the cost of knowing them."
Lin Ze took her hand. "I promise."
She searched his face, then gave a small, sad nod. "Then go. But I won't come with you. I've carried those ghosts long enough."
Lin Ze stood, key clenched in his fist. He paused at the door.
"Grandma… thank you. For trusting me."
She managed a faint smile. "I'm not trusting you, Ah Ze. I'm trusting that you're stronger than he was."
He left her sitting among the porcelain shards and climbed the narrow stairs to the attic alone.
The door creaked open into darkness. Dust motes danced in the thin beam of his phone flashlight. The wooden box waited exactly as before—patient, silent, inevitable.
Lin Ze knelt, heart racing. The red key slid into the lock with a soft, perfect snick.
He hesitated one last time, Grandmother's warning echoing: Some truths aren't worth the cost.
Then he turned the key.
The lock clicked open.
Cool air breathed from within, carrying the faint scent of old paper and something metallic.
Lin Ze lifted the lid.
Inside were dozens of manila folders, edges yellowed with age, labels in Grandfather's precise handwriting. Dates from forty years ago to just months before his death. On top lay a single folder thicker than the rest, bound with red string.
Written across it in bold, fresh ink:
FOR WHOEVER FINDS THIS READ IN ORDER DO NOT REMOVE FROM THE HOUSE SOME TRUTHS CANNOT BE CARRIED ALONE
Lin Ze's fingers trembled as he untied the string.
The first page was a handwritten note in Grandfather's familiar script:
"If you are reading this, I am gone. These are the cases I could not close. Not for lack of evidence. But because the truth was worse than ignorance. Read if you must. But remember: Once you know, you cannot unknow. And some doors, once opened, let things through both ways."
Lin Ze turned the page.
The first file began:
Case No. 1 – The Midnight Knocker
Location: An old tong lau in the rundown district of the city, 6th floor, Room 603.
Client: Anonymous (paid in cash, voice deliberately lowered).
Phenomenon: Every night at exactly 3:00 a.m., someone knocks on the door. Three knocks—light, rhythmic. Open the door: nothing. The corridor is empty. No footsteps on the stairs. Later-installed security cameras captured absolutely nothing.
Lin Ze's breath caught.
He glanced toward the attic stairs, suddenly aware of how alone he was.
Then he began to read.