You ever have one of those moments where something weird happens, and you just brush it off?

That was me.

I was the queen of eh, it's probably nothing.

A woman sitting on a couch and smiling | Source: Midjourney

So, when I found a yellow Post-it note on my desk, one that I definitely hadn't written, I didn't spiral into paranoia at first. The note was in weird, wobbly handwriting, reminding me to pick up cucumbers and crackers when I did groceries and mail a letter.

Things that I'd thought about doing, sure. But I hadn't told anyone about doing those things. And yet, there it was, sitting right in the middle of my desk like a to-do list from a ghost.

I frowned at it, checked my phone calendar to see if I'd set a reminder and forgotten about it, then shrugged. Maybe I'd scribbled it down half-asleep. Maybe my brain was doing that fun thing where it made me question my own reality.

A woman sitting at a desk | Source: Midjourney

But also... who even mailed letters anymore? I emailed people. Unless it was a package I needed to mail? But what package?

I had no clue.

So I tossed it in the trash and moved on.

A box on a coffee table | Source: Midjourney

A few days later, another note appeared. It was the same shaky handwriting on one of the same yellow Post-its.

Make sure you save your documents.

Okay.

Now, that was a bit creepier.

"What the hell, Mila?" I asked myself. "What are you on, girl?"

A person writing on a Post-it note | Source: Midjourney

I was a freelance writer, and I'd been working on a big project the night before.

No way. No. Absolutely not.

I lived alone. My door had been locked. There were no signs of a break-in. There were no misplaced or stolen items that I could see. Just the note.

I told myself it was probably stress, that I was working too much and not sleeping enough. So, I just threw it away again.

A woman holding her head | Source: Midjourney

It was almost midnight, and I wasn't sure what broke my sleep, but suddenly, I was awake and looking at another note that I found on my side table. This time, it didn't feel harmless.

Our landlord isn't letting me talk to you, but it's important that we do.

I sat frozen in my desk chair, rereading the words over and over again. My mouth was dry.

The air in my apartment suddenly felt wrong.

Who the heck was writing these notes? And why was my landlord now involved?

A woman sitting at the edge of her bed | Source: Midjourney

I tore through my apartment, checking the locks and the windows. There were absolutely no signs of forced entry. My landlord did have a key to the apartment, but I didn't expect him to come in on his own. Usually, we arranged a day and time if I needed anything fixed.

But when I sat down, another realization hit me, my webcam. Surely that would provide some evidence?

I had set up an old webcam on my desk after the first note, using a security cam app to record whenever it detected movement.

A webcam on a table | Source: Midjourney

I scrambled to check the folder. The files were gone.

Not just missing. They were deleted.

My stomach turned at the thought. I hadn't touched them. The only way they could be gone was if someone else had deleted them.

Then another thought hit me, the recycle bin.

A woman using her laptop | Source: Midjourney

But even that was empty.

Someone, who wasn't me, had noticed the camera, gone into my laptop, and erased the footage.

I forced myself to stay calm, but I was terrified. I went to the kitchen, grabbed a knife, double-checked the locks, and went back to bed. I couldn't sleep, but it was the safest place to be. Or so I thought.

A knife block in a kitchen | Source: Midjourney

The next day, when I got home from the gym, there was another Post-it. But this one was different.

It was stuck to the outside of my apartment door, blank. There was no message, no shaky handwriting. It was just a pale yellow square pressed against the wood like a silent warning.

The hair on my arms stood.

I yanked it off, my hands shaking. Was someone telling me that they were watching? That they knew I'd noticed the notes? That they knew I wasn't home?

A blank Post-it on a door | Source: Midjourney

A sick feeling crawled up my spine. As I turned to head back inside, I noticed something else.

Other doors in my building had them too.

Different colors. Pink, blue, and yellow. But all were blank.

I stood there, my breath coming too fast, watching my neighbor's door across the hall. Had they put one up too? Had someone done this to all of us?

A woman standing in a hallway | Source: Midjourney

I didn't wait to find out. That was it. I was done. I grabbed my keys and bolted out of my apartment.

Jessica opened her front door in an oversized hoodie, her hair a mess.

"Mila? It's..." She turned around and squinted at the clock in her living room.

"Dude, it's almost ten! I was just heading to bed. What's going on?"

A woman standing in a doorway | Source: Midjourney

I pushed past her, pacing into her tiny living room.

"I need you to tell me that I'm not crazy."

Jessica rubbed her eyes, shutting the door behind her.

"Okay, but we're going to need some coffee. And I swear, Mila, if this is about aliens again, I'm going to smack you with something."

A kettle on a counter | Source: Midjourney

"No," I snapped. "This is much worse, Jess. I think someone's been in my apartment."

That woke her up. She sat down on the couch, watching me with concern as I explained everything, the Post-it notes, the deleted security footage, and the empty recycle bin. My voice cracked more than once, and I knew that I was visibly trembling.

Jess didn't interrupt, just nodded along, her brows drawn tight in thought.

When I finished, she exhaled.

A shocked woman | Source: Midjourney

"But there's been no trace of another person in the apartment?"

"Absolutely none! I don't know if they've just been really good at covering up their tracks or if they're ghosts. I'm serious, Jess. I haven't seen anything out of the ordinary, but I know that something is wrong."

"Mila, have you checked for carbon monoxide?"

A shocked woman holding her head | Source: Midjourney

"What?" I blinked.

"CO poisoning, girl," she said. "It can cause memory issues, disorientation, and even paranoia. What if you're writing the notes yourself and just... not remembering?"

I wanted to argue. I knew my own handwriting. But the more I thought about it, the more the idea gnawed at me.

Hadn't I been feeling off lately?

A scared woman sitting on a couch | Source: Midjourney

I'd been waking up with headaches, feeling exhausted no matter how much I slept. My thoughts had been cloudy and slow. And I had struggled to do a basic workout at the gym too.

Maybe the notes weren't from some stranger. Maybe my own brain was betraying me.

I left Jessica's place and drove to a gas station, one of the only places still open this late.

The exterior of a gas station | Source: Midjourney

"Can I help you?" the cashier asked. "We did rearrange the store."

"A carbon monoxide detector, please," I said, sure that my voice sounded thin and weak.

"Sure, aisle three," he said.

The interior of a gas station store | Source: Midjourney

Back at my apartment, I plugged it in my bedroom. The number on the screen shot up immediately. 100 ppm.

I barely had time to process that before the dizziness hit me like a wave. The air suddenly felt thick, pressing down on me.

I grabbed my bag, yanked open my front door, and stumbled into the hallway, gulping in fresh air.

"Jess," I said when she answered.

"Are you okay?" she asked.

"No, I need you now! The reading was insane!"

A carbon monoxide detector | Source: Midjourney

"I'm coming. Stay outside. Get in some fresh air, Mila."

A doctor in navy scrubs stood by my hospital bed, flipping through my chart.

"You're lucky you caught this when you did, Mila," he said. "Prolonged exposure at 100 ppm can be deadly. You weren't at immediate risk of suffocating, but with constant exposure, it could have caused permanent cognitive damage. Eventually, you might have lost consciousness and never woken up."

"I... how long would I have had?" I stared at him. "If I didn't come in, I mean."

A smiling doctor | Source: Midjourney

"Weeks, maybe less, Mila. This is serious business," he said, giving me a grim look.

I swallowed hard.

Jessica, sitting beside me, squeezed my hand.

"You're okay now, Mila," she murmured. "And that's what matters."

The doctor nodded.

"You made the right call. Carbon monoxide poisoning is tricky. It's called the silent killer for a reason—no smell, no taste, no warning signs. If you hadn't plugged in that detector..."

He didn't finish the sentence. He didn't have to.

A woman in a hospital bed | Source: Midjourney

The next day, I called Greg, my landlord. He didn't sound shocked.

Not even a little.

He muttered something about "getting it checked" and hung up fast. That didn't sit right with me, so I called the city inspector myself. And that's when I learned the real nightmare.

The leak wasn't just in my apartment. It was coming from the building's parking garage.

An apartment parking lot | Source: Midjourney

And my unit? It was directly above it.

I was breathing in CO seeping up from below, trapped in my apartment like a slow-motion death sentence.

"Are you going to sort it out?" I asked Greg when I went over to his office a few days later. I had been staying with Jess, but her boyfriend's patience was growing thin.

A grumpy man | Source: Midjourney

"Yes, Mila," Greg said. "But I can't tell you when. You should take your belongings and go stay with family or something."

I moved in with my cousin, who lived across town while it got sorted. The inspector contacted my neighbors, but apparently, my apartment had been hit the worst.

Now that I'm safe, I keep thinking about what would have happened if I hadn't told Jessica. If I had dismissed it all as paranoia.

But the worst part?

A woman looking out of a window | Source: Midjourney

I still don't know why I wrote that third note.

Our landlord isn't letting me talk to you, but it's important that we do.

Was that my subconscious trying to warn me? A part of my brain screaming for help while the rest of me slipped further into confusion?

Or was someone, something else trying to get my attention?

I don't have answers.

A woman holding her head | Source: Midjourney

I wasn't planning on going back to my apartment. My cousin had asked me to move in with her permanently. But I had to grab the last of my things before leaving for good.

The air inside felt all wrong. Even knowing that the gas was shut off, my chest tightened the second I stepped in. I stuffed the last of my clothes into a duffel bag and was about to leave when a voice stopped me.

"Mila."

I turned to see my landlord, Greg, standing in the hallway. He was an older man with a permanent scowl on his face. He seemed to just hate his job.

A pink duffle bag | Source: Midjourney

"You're moving out?" he asked.

"You knew," I replied.

"I didn't know that you were moving, Mila," he said.

"The leak, Greg. You knew about the leak. You weren't surprised when I called. You knew. How long has it been there? How many other tenants have complained?"

His jaw tightened.

A grumpy man | Source: Midjourney

"I don't know what you're talking about, Mila."

"Right, and those blank Post-it notes on other doors? Just a coincidence?"

For a second, just a second, something flickered across his face. Then, as quickly as it came, it was gone.

"You should go," he said flatly. "I came to make sure that the reading of your apartment was fine."

A woman standing in an apartment | Source: Midjourney

I stood there, heart hammering, staring at the closed door. Something told me that I wasn't the first person this had happened to. And I wouldn't be the last.

But I do have one piece of advice for you:

If weird things start happening, don't ignore them. Because sometimes, paranoia isn't paranoia at all. Sometimes, it's survival.

A woman standing by a window | Source: Midjourney

What would you have done?

If you've enjoyed this story, here's

another one

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My dream apartment turned into a living nightmare when I began receiving threatening notes, each more chilling than the last. When I discovered who was behind them, my blood froze, and my life was never the same.

This work is inspired by real events and people, but it has been fictionalized for creative purposes. Names, characters, and details have been changed to protect privacy and enhance the narrative. Any resemblance to actual persons, living or dead, or actual events is purely coincidental and not intended by the author.

The author and publisher make no claims to the accuracy of events or the portrayal of characters and are not liable for any misinterpretation. This story is provided "as is," and any opinions expressed are those of the characters and do not reflect the views of the author or publisher.