The dream clung to Lin Ze like damp fog all morning.
He sat at his desk in the open-plan office, staring at structural drawings that might as well have been written in another language. Columns of numbers blurred together. Load calculations refused to make sense. Every time he tried to focus, the silhouette returned: long hair, tilted head, that impossible smile stretching too wide.
"You already opened the door."
His supervisor walked past twice, frowning at the untouched coffee cooling beside Lin Ze's keyboard. A colleague asked if he was feeling all right. Lin Ze muttered something about a late night and forced a smile that felt plastic on his face.
By lunchtime he gave up pretending. He texted Xiao Mei:
Can we meet after work? Need to talk about something weird.
Her reply came almost instantly:
Weird how? Ghost weird or boyfriend-finally-proposing weird? 😏
Meet you at the café near your office. 6 pm?
He smiled despite himself. Xiao Mei—his girlfriend of two years—had a way of making even the heaviest things feel lighter.
They met at the usual corner café, the one with the mismatched chairs and overpriced lattes. Xiao Mei was already there, wavy hair tied back, nursing an iced matcha. She worked as a graphic designer, freelance, which meant her schedule was flexible and her patience for Lin Ze's occasional brooding was generous.
He slid into the seat opposite her.
"You look like you haven't slept in a week," she said, reaching across to touch his cheek. "What's going on?"
Lin Ze hesitated. How do you tell someone you love that you found your dead grandfather's secret box of unsolved cases, opened it against everyone's advice, saw a ghost in an old photograph, and now it's following you into dreams?
He started slow: Grandfather's death, clearing the attic, the locked box, the red key hidden in the vase. Grandmother's reluctant permission. The first file—the Midnight Knocker.
Xiao Mei listened without interrupting, eyes growing wider with every detail.
When he reached the part about the photograph and the vanishing shadow, then the nightmare that woke him at exactly 3:02 a.m., she leaned back and whistled low.
"Okay… that's properly creepy."
"I know it sounds insane," he said quickly. "I keep telling myself it's stress, lack of sleep, imagination. But it feels… real."
Xiao Mei stirred her drink thoughtfully.
"You know what I think?"
"That I should see a therapist?"
She laughed. "Well, maybe. But also… what if you're supposed to finish what your grandfather couldn't? Like fate or something. The key literally fell into your hands. The box was waiting for you."
Lin Ze stared at her. "You're not supposed to encourage the crazy."
"I'm serious!" She grinned, eyes sparkling with mischief. "Think about it. Your name is Lin Ze. Ze Feng—sounds exactly like 'detective' in Cantonese. Ze the Detective. It's destiny."
He groaned, but couldn't help laughing. "You're ridiculous."
"Ridiculously right," she corrected. "Look, if it's bothering you this much, sitting here worrying isn't going to help. Why don't we go see the place? The actual building. Maybe seeing it in daylight will make it less scary. Or… maybe you'll find something your grandfather missed."
Lin Ze blinked. "You want to go to a possibly haunted apartment building with me?"
"I want to go on an adventure with my boyfriend who's turning into Ze the Detective." She winked. "Besides, it's broad daylight. Ghosts hate daylight, right?"
He should have said no. Should have listened to Grandmother's warnings. Should have closed the drawer on the red key and never thought about it again.
Instead he heard himself say, "Okay. Let's go after work."
The old district hadn't changed much since 1987.
Narrow streets, laundry hanging from bamboo poles, the smell of street food mixing with exhaust fumes. The tong lau in question stood at the end of a dim alley—six stories, grimy concrete, rusted balconies sagging under potted plants and air-conditioner units.
Lin Ze and Xiao Mei stood across the street, staring up.
"Room 603," Lin Ze murmured, checking the address Grandfather had written nearly forty years ago. "Top floor, left side."
The building looked tired, but not sinister. Kids kicked a soccer ball in the alley. An old man smoked on a stool outside the ground-floor mahjong parlor. Normal life.
"Doesn't look haunted," Xiao Mei said cheerfully. "Come on, Ze Detective. Let's investigate."
They crossed the street. The entrance was an open archway leading to a dim stairwell. No elevator, of course. A faded directory board listed residents, but most names were scratched out or missing.
Lin Ze's pulse quickened as they climbed. The stairs were narrow, walls stained with years of handprints. Each landing smelled faintly of cooking oil and incense.
Second floor. Third. Fourth.
On the fifth-floor landing, Xiao Mei paused. "You okay? You're breathing like we just ran a marathon."
"I'm fine," he lied.
Sixth floor.
The hallway was exactly as in the photograph: long, narrow, flickering fluorescent light. Water stains on the walls. Doors on either side, most with shoes outside or children's toys.
Room 603 was at the far end.
The door had been repainted a bright blue—someone's attempt at cheerfulness—but the frame was still the same old wood. The number plate was new, shiny metal.
Lin Ze stood in front of it, memories of the dream flooding back. Three knocks. Breathing at his ear. The mirror.
Xiao Mei squeezed his hand. "Want to knock? See if anyone's home?"
He hesitated. "The file said the client moved out years ago. Probably new tenants now."
As if on cue, the door opened.
A middle-aged woman stepped out carrying a trash bag. She wore an apron, hair in curlers. She glanced at them curiously.
"Looking for someone?"
Lin Ze found his voice. "Uh… no, sorry. We were just… my grandfather used to live in this building a long time ago. I was showing my girlfriend around."
The woman smiled politely. "Oh, this building's old. Lots of people come and go. We've only been here five years."
Xiao Mei jumped in smoothly. "Any… strange stories about the place? Old buildings always have ghost tales, right?"
The woman laughed, but there was a nervous edge to it. "This building? Plenty. People say the sixth floor is bad luck. Tenants never stay long in 603. Before us, a young couple moved out after six months. Said they heard knocking at night. We thought they were crazy—until we heard it too."
Lin Ze's blood went cold.
"Knocking?" he asked, voice barely above a whisper.
"Every night at three," the woman said, lowering her voice as if the walls might hear. "Three knocks. We open the door—nothing. Installed a camera once. Recorded empty hallway. We got used to it. Or pretended to. My husband says it's the pipes. But…" She shrugged, uncomfortable. "We're moving next month anyway."
She nodded goodbye and headed downstairs with her trash.
Lin Ze and Xiao Mei stood in silence.
Xiao Mei broke it first. "Okay… not going to lie, that's freaky."
Lin Ze stared at the blue door. The dream whispered at the edge of his mind.
You already opened the door.
"We should go," he said abruptly.
But as they turned to leave, Xiao Mei grabbed his arm.
"Wait. Look."
She pointed at the peephole in the door. From this angle, the convex glass acted like a fish-eye lens, reflecting a distorted view of the hallway behind them.
In the reflection, for a split second, Lin Ze saw it.
A woman's silhouette.
Long hair. Tilted head.
Standing right behind him.
He spun around.
The hallway was empty.
Xiao Mei hadn't seen it. She was still looking at the door.
Lin Ze's heart hammered so hard he thought it might burst.
"Come on," he said, voice shaking. "Let's get out of here."
They hurried down the stairs, not speaking until they were back on the street, daylight and noise surrounding them again.
Xiao Mei exhaled. "Okay, Ze Detective. Your grandfather definitely wasn't imagining things."
Lin Ze looked back at the building. Somewhere up there, on the sixth floor, something was waiting.
And it knew he had come.