Forbidden Rule 1 Don't answer the phone at 3:33 a.m.
People often say that 3:33 a.m. is the strangest time of night. If your phone rings at exactly that time and the screen only displays two words—"Unknown Number"—let it ring until it stops on its own. Don't get curious. Don't answer. Because after that call... There may not be anyone left who can call you again.
Minh was a software engineer who lived alone in a thirteenth-floor apartment in an old apartment building. Because of his work, he was often awake until nearly dawn. That night, Minh had just finished saving a design when the clock in the corner of his screen changed to 03:33. Right then... His phone vibrated. An unknown phone number. No name. No profile picture. No country. Just a long string of numbers Minh had never seen before. He stared at the screen for a few seconds, then pressed Decline. The ring stopped immediately. Minh let out a sigh of relief. But less than three seconds later... His phone vibrated again. The same number. This time, whether out of curiosity or annoyance, Minh pressed Answer. There was no voice on the other end. Only a hiss of static. Then... A hoarse male voice rang out. "Finally... someone answered." A chill ran down Minh's spine. "Who are you?" The voice on the other end chuckled. "Don't ask who I am." "Look out the window." Minh turned his head without thinking. Outside the window were only the darkness of night and rows of pitch-black buildings. "There's nothing there." "There is." "Someone is watching you." Minh frowned. "Are you kidding me?" The other end fell silent for a few seconds. Then it asked slowly: "You're on the thirteenth floor..." "...aren't you?" Minh's hand went rigid. He had never given the caller his address. "I also know..." "...the light in your living room is still on." Minh flinched and looked toward the living room. The light was still on. A cold current ran down his spine. "Who are you?" There was no reply. Only breathing. Steady. As if the other person were standing very close to the microphone. Then the call ended.
The next morning, Minh told the apartment security guard what had happened. After listening, the old man asked: "What time did the call come in?" "Three thirty-three." The old man's face suddenly went pale. He silently opened a drawer and took out an old ledger yellowed with age. It contained page after page of dates. Each page had a name on it. Beside it was the time of the call: 03:33 The final page was still blank. The old man stared at Minh for a long time, then said softly: "Last night..." "...the ledger wrote in your name by itself." Minh laughed, thinking it was just a prank meant to scare him. But when he bent down to look again... Fresh ink had appeared on the ledger's final line. MINH 03:33 Beneath it was a smaller line of writing. "The second call will come exactly seven days from now."
Forbidden Rule 2 Don't answer when someone calls your name from behind while you're alone.
"A person's name should only be called by the living." That was what Grandma often reminded him whenever night fell. Hai had never believed it. He was a delivery driver who usually finished work nearly at midnight. The road home included a stretch of the embankment road more than a kilometer long. It was crowded during the day, but after eleven at night, hardly anyone passed through.
That night, Hai finished work late. The wind was bitingly cold. There was only the sound of his motorcycle and the relentless chirping of insects. As he rode, he clearly heard a woman's voice behind him. "Hai..." He glanced at the rearview mirror. There was no one there. Thinking he had imagined it, Hai kept riding. A few dozen meters later. "Hai..." This time, the voice was closer. As if someone were sitting right behind him on the motorcycle. Hai slammed on the brakes. The road was still deserted. On either side were only rice fields submerged in darkness. He gave an awkward laugh. "I must be hallucinating because I'm too tired." Hai had just started the engine when the voice came a third time. "Hai..." "...wait for me, son." His heart seemed to stop. His mother had been dead for nearly four years. That voice... It was exactly the same. Tears suddenly welled in Hai's eyes. He answered softly: "Mom...?" The instant the words left his mouth, the insects around him abruptly fell silent. The wind stopped blowing too. The entire world sank into a terrifying silence. The motorcycle shut off by itself. The headlight went out. In the darkness, Hai felt breath against the back of his neck. Cold as ice. A hand settled lightly on his shoulder. Then a voice spoke right beside his ear. "Finally..." "...you decided to answer."
The next morning, people found the motorcycle parked by the roadside. The key was still in the ignition. His phone was still in the storage compartment. His wallet was untouched. Only Hai was gone.
Three days later. An old duck herder said that every night when he passed along the embankment road, he saw a young man standing in the middle of the road with his back turned. If anyone passed by... The young man would call that person's name. In the voice of the loved one they missed most.
A Note in the 99 Forbidden Rules If you hear someone call your name from behind when you know for certain that no one is there... Don't answer. Don't turn around. And absolutely... Don't let that voice become familiar.
Forbidden Rule 3 Don't pick up a key outside your door if you're certain it isn't yours.
7:00 p.m. A light rain was falling. Vy had just finished work when she saw an old brass key outside the door of her apartment. She bent down and picked it up. "Someone must have dropped it." The key was unusually heavy, and a single number was engraved on its shaft: 404 The strange thing was that the apartment building where Vy lived only had four floors. There was no Apartment 404. Vy took the key into her apartment, intending to turn it in to the building management the next day.
That night... At exactly 1:17 a.m. Metal clinked against metal. Clink... Clink... Vy opened her eyes. The sound was coming from right outside her door. She looked through the peephole. There was no one there. But the keys kept jingling. Clink... As if someone were holding an entire ring of keys and trying them one by one to open her door. Then... "Click." The lock turned with a soft sound. Vy rushed over in alarm. The door was still locked. The deadbolt was still in place. Then what door... "...had just been unlocked?"
The next morning, the key was gone. Vy thought she had probably left it somewhere. But from that day on, footsteps always echoed through the hallway at exactly 1:17 a.m. Not fast. Not slow. The person walked from the far end of the hall... "...to the door of Vy's apartment." Stood there for exactly one minute. Then walked away.
On the seventh night. The footsteps stopped. They didn't leave. There was a knock at the door. Once. Twice. Three times. Then came the voice of an old man. "You dropped my key." Vy trembled. "I... I didn't." Silence came from outside. Then the voice spoke again. "Then why..." "...did you open my door?"
The next morning, Vy went downstairs to speak with the building management. The elderly manager's expression changed when he heard the story. He showed her the building's old blueprints. The plans clearly showed that the fourth floor had once contained Apartment 404. But the room had been sealed off more than thirty years ago after someone disappeared. No one knew where that door led. No one had ever found the key. Until... Vy picked it up.
Three days later, the neighbors discovered that the door to Vy's apartment was still locked from the inside. All her belongings were untouched. Her phone was still charging. The kettle was still hot. Only one thing was missing. That was... the living room door. On the wall where the door had once been, only a perfectly smooth coat of paint remained. As if the apartment... had never had an entrance.
A Note in the 99 Forbidden Rules Some keys aren't meant to open locks. They're meant to open a place that's trying to forget you ever existed.
Forbidden Rule 4 Don't look up if you hear a marble rolling across the ceiling.
Everyone who lives in an old apartment building knows one thing. If you hear a marble rolling across the ceiling at midnight, ignore it. Don't count. Don't try to find out where the sound is coming from. And absolutely... Don't look at the ceiling.
Nam had moved into Apartment 608 three days earlier. The apartment was clean, and the rent was surprisingly cheap. There was only one strange rule the landlady repeated before handing over the keys: "If you hear a marble rolling at night, just go to sleep. Don't get curious." Nam only smiled. He figured it was probably a child upstairs.
The first night. 2:14 a.m. "Clack..." A very soft sound. Then... Roll... clack... roll... clack... It sounded like a glass marble rolling from one end of the apartment to the other. Nam opened his eyes. The sound of the marble lasted nearly a minute, then stopped completely.
The next morning, he went upstairs. The strange thing was that the apartment directly above his... had been locked for years. A thick layer of dust covered the lock. Building management confirmed that no one lived there. Nam laughed. "The sound must have carried."
The second night. The sound of the marble returned. This time, it was closer. Roll... clack... Roll... clack... As if it were circling directly above his bed. Nam used his phone to record it. When he played it back... There was no sound of a marble. Only a very soft child's voice. "Can you hear me?" Nam's blood ran cold. He deleted the recording. He told himself he wouldn't pay attention anymore.
The third night. The sound was no longer above the ceiling. It came... from inside the wall. Roll... Clack... Roll... Clack... As if a marble were rolling through the concrete. Then it stopped abruptly, right behind the head of his bed. Everything fell utterly silent. Nam held his breath. Three seconds later. A child's voice rang out clearly. "Mister..." "...look up."
Nam clutched the blanket. He remembered the landlady's warning. Don't look. Not even once. The voice disappeared. He let out a sigh of relief. Right then... His phone screen lit up. A notification appeared. Front camera in use. Nam hadn't even had time to understand what was happening. The screen switched to camera mode by itself. On the phone's screen was his own terrified face. And... Right above his head, pressed against the ceiling... a little girl was crawling upside down. Her long hair hung down, just a few centimeters from Nam's face. The most horrifying thing was... the girl wasn't looking at Nam. She was staring straight at you. As if she knew someone would pick up a phone to read this story.
A Note in the 99 Forbidden Rules Some sounds aren't meant for you to hear. They're only checking... whether you're curious enough to look up or not.