— Don’t go to work tomorrow. Just trust me and stay home! my neighbor warned me, trembling with fear.

— Don’t go to work tomorrow. Just trust me and stay home! my neighbor warned me, trembling with fear.

A knock on the door came exactly at midnight. I knew that for sure, because I had just checked my phone. I still couldn’t fall asleep—had been tossing and turning for almost an hour, thinking about tomorrow’s planning meeting.

At first, I decided not to open. Who even comes at a time like that? But the knocking came again. Insistent, but not aggressive—more desperate than anything.

“Liza, it’s me, Katya. Please open up.”

My neighbor from the fifth floor…

We greeted each other in the elevator, sometimes exchanged a few words about the weather or the renovation in the stairwell, but we weren’t close. She was an ordinary thirty-something Muscovite, always rushing somewhere with a phone pressed to her ear. She worked—if I remembered right—at some IT company.

I threw on a robe and opened the door. Katya stood there in pajamas and slippers, hair messy, eyes red. She was nervously gripping her phone.

“Sorry for waking you,” she started, not even waiting to be invited in. “I know how this looks, but I need to tell you something. Something very important.”

“What happened?” I let her into the entryway. “You look like you’ve seen a ghost.”

“Don’t go to work tomorrow,” Katya blurted, staring straight into my eyes. “Just trust me and stay home!”

I blinked. That was the last thing I expected to hear.

“What? Katya, are you okay? Should I call a doctor?”

“I’m fine, it’s just…” She swallowed, still shaking. “You’ll understand closer to lunchtime. Liza, I’m serious. Don’t leave the house tomorrow. At all. Call in sick, make something up—anything—but don’t go to work.”

We stood facing each other in the narrow entryway, and for the first time I really looked at her. Normally she always seemed calm. Now she was rattled and terrified.

“Why are you telling me this?” I asked. “We barely know each other.”

“Because…” Katya hesitated and rubbed her forehead nervously. “Because I have to. You’re a good person. You always smile in the elevator, and once you helped me carry my bags when I’d bought groceries for the whole week. Remember? About two months ago.”

I vaguely remembered. The elevator had broken, we’d climbed the stairs, and she’d had huge shopping bags. I’d just shown ordinary neighborly courtesy.

“Katya, explain properly. What is supposed to happen tomorrow?”

She shook her head.

“I can’t. But please believe me. Just stay home. And tomorrow evening, if you want, come over to my place. I’ll tell you everything.”

“Do you realize how this sounds? I have an important meeting tomorrow—I’ve been preparing for three weeks. A new project, a big budget…”

“Liza!” Katya grabbed my hand; her fingers were icy cold. “I’m begging you!”

We were silent for a few seconds. I studied her face, trying to figure out what I was dealing with. A nervous breakdown? A mental disorder? Or did she really know something I didn’t?

“Okay,” I finally said. “I’ll try.”

Katya exhaled with relief.

“Thank you. Really—thank you so much.”

She turned and headed for the door.

“And don’t leave the apartment at all. Until evening. Promise?”

“I promise I’ll try.”

After Katya left, I couldn’t fall asleep for a long time. I tossed and turned, replaying her words and that look in her eyes.

What could she possibly know that I didn’t? Maybe layoffs were coming at our company? But what did that have to do with “don’t leave the house at all”?

At six in the morning, my alarm rang as usual.

I got up, made coffee, and sat down to breakfast. Then I caught myself constantly glancing at my phone. The anxiety wouldn’t let go.

At seven thirty, I finally texted my boss that I felt unwell and wouldn’t be coming in. I don’t like lying, but something about Katya’s behavior got under my skin.

Intuition, I guess…

The day crawled by painfully slowly.

I tried to keep busy with chores: sorted out the closet, washed the windows, even started reading a book I’d bought last year.

But my thoughts kept returning to my neighbor’s midnight visit.

At ten in the morning, my friend Oksana called.

“Why are you at home? Sick?”

“Sort of. How do you know?”

“Because I work near your office. I wanted to have lunch together, stopped by to invite you to a café—and you weren’t there.”

“Listen, is everything calm in your area? Nothing strange going on?”

“Seems like a normal day. Liz, are you sure you’re okay? You sound kind of anxious.”

I didn’t tell her anything about Katya. I didn’t fully understand what was happening myself.

By noon, my patience snapped. I decided to get ready and go to the office. I mean, what could possibly happen in broad daylight in the center of Moscow?

But then there was another knock at the door.

This time it was Aunt Zina, the elderly neighbor from the third floor. She was holding a tray of pastries.

“Lizzie, sweetheart, I heard you weren’t feeling well. Here—cabbage pies, still hot.”

“Thank you so much. Please, come in.”

Aunt Zina walked into the kitchen, set the tray on the table, and looked at me in a strange way.

“Did Katyusha come to see you last night?” she suddenly asked.

“How do you know?”

“Oh, I heard the door slam. My sleep has gotten light with age!” She paused, then added, “Good thing you listened to her.”

A chill ran down my spine.

“Aunt Zina… do you know something?”

The old woman shook her head.

“I don’t know anything myself. But Katyusha is a special girl. She has… how do I put it… a kind of sense. Remember two months ago, when she told everyone in the building to stock up on water? Said it would be shut off for a week. Nobody believed her, and she was hauling around three-liter jars. And then the pipe really did burst—and we sat without water for four days.”

I vaguely remembered that story. Back then, everyone had laughed at Katya’s “over-preparedness.”

“So what—she’s psychic?”

“No, of course not. Just a normal girl, works as a programmer. It’s just that sometimes… she knows things she shouldn’t be able to know. Her intuition is very strong.”

After Aunt Zina left, I was completely thrown. One thing is a strange request from a neighbor you barely know; it’s another when people who’ve known her for years actually believe her.

At one o’clock, someone called me from an unknown number.

“Elizaveta Sergeyevna Volkova? This is Senior Lieutenant Petrov, police. Could you come in to give a statement?”

My heart dropped into my stomach.

“A statement? About what?”

“This morning there was an incident in the building where your office is located. No one was injured, but we need to speak with employees of Alliance-Project.”

“What incident?”

“We don’t discuss details over the phone. When can you come?”

I looked at the clock. Exactly one p.m.

“What exactly happened? I’m on sick leave today—I’m at home.”

“All the better. Then it didn’t affect you directly. But we still need to talk. Would tomorrow morning work?”

“It would.”

After the call with the police officer, I just sat at the kitchen table for half an hour, staring at one spot. Katya knew. Somehow, she knew something would happen at our office. And she warned me.

But how? And most importantly—why me?

I tried calling my coworkers, but their phones either didn’t answer or were unreachable. The corporate chat was silent too. The last messages were dated yesterday evening.

At four o’clock, I couldn’t take it anymore and went up to the fifth floor.

Katya opened the door quickly, as if she’d been waiting for me. She looked much better than she had at night, but there was still a guarded wariness in her eyes.

“Come in,” she said simply. “Want some tea?”

“Yes, thanks. The police called me,” I said, sitting down on the couch. “Something happened at our office.”

Katya nodded, pouring tea from a thermos.

“A collapse. A floor slab on the eighth floor gave way. Right above your office.”

“What?!” I sprang up. “And people—was anyone hurt?”

“No. Everyone got out in time. The building was evacuated at nine thirty, right after an engineer noticed cracks in the ceiling. The slab fell at eleven forty.”

I sank back onto the couch, trying to process what I’d just heard. If I’d gone to work like usual…

“How do you know all this? And how did you know in advance that it would happen?..”

Katya was silent for a moment, then sat down across from me.

“I didn’t know exactly what would happen. But I knew something would. And that it would be connected to your building.”

“So what, you’re clairvoyant?”

“No,” Katya gave a bitter little smile. “I’m a hacker. Or rather, I was. Now I work in information security.”

“And what does that have to do with a collapse?”

“A month ago I was working on a project—doing a security audit for an insurance company. As part of the job I had to study their real estate database. And I stumbled on something interesting.”

Katya stood up, went to one of the computers, and opened something on the screen.

“See these documents? Technical inspections of buildings. The official conclusions say everything’s fine. But these files are the real engineers’ reports. They were buried in archives, but I found them.”

Tables, diagrams, and photos of cracks in concrete flashed across the monitor.

“Your building has been high-risk for two years. Microcracks in the slabs, loads above the limit, violations during reconstruction. But the management company and the insurers swept it under the rug. It was cheaper to bribe the experts than to do a major overhaul.”

“You mean they knew it could collapse and kept quiet?”

“Exactly!” Katya turned to me. “And last night I found out a commission from city hall was supposed to come today. An unannounced inspection. Someone finally decided to push the investigation through.”

I listened, feeling everything inside me go cold.

“So the collapse wasn’t an accident?”

“Hard to say. Maybe it was just a coincidence. Or maybe someone decided it would be better if the building ‘fell on its own’ than if it got shut down for violations. Fewer questions that way.”

“And you knew all this in advance?”

“Not all of it. I only knew the building was dangerous and that something was supposed to happen there today. That’s why I came to you,” Katya glanced out the window. “Honestly, I thought you wouldn’t believe me and would tell me to get lost.”

We fell silent.

I tried to digest it all. Someone had been putting people’s lives at risk for years to save money. And my neighbor—someone I barely knew—had risked looking insane just to save my life.

“Why did you help me?” I finally asked. “We hardly talk.”

“I don’t know,” Katya admitted. “Maybe because you’re the only one in the building who greets me sincerely. Or maybe because I had information that could save someone, and staying silent would’ve been a crime.”

“And what are you going to do with those documents now?”

Katya smiled, and for the first time I saw something like satisfaction in her eyes.

“I already sent them off. To the prosecutor’s office, the Investigative Committee, and journalists. Anonymously, of course. I think tomorrow or the day after, a very interesting investigation will begin.”

The next day I went to the police station after all.

Our office building was cordoned off. People in hard hats bustled around, taking photos and measurements. It looked terrifying—especially when you realize that just yesterday morning you could have been inside.

Senior Lieutenant Petrov studied me carefully from head to toe and offered me a seat.

“Tell me about your job at the company,” he said. “How long have you worked there, and did you know anything about problems with the building?”

I told him everything I knew.

That sometimes I’d heard creaking in the ceiling. That a year ago a crack appeared in the restroom wall, but it was quickly plastered over. That the management company always brushed off tenants’ complaints.

“And why didn’t you come to work yesterday?” Petrov asked. “Your sick note says ARVI, but you don’t look ill.”

I hesitated. I didn’t want to mention Katya—I was afraid I could put her in danger.

“I really wasn’t feeling well. By evening I felt better.”

“Understood,” the investigator scribbled something down. “If you remember anything else important, call.”

As I was leaving, Oksana called.

“Liz, have you seen the news? They’re writing about your building!”

At home I opened the internet. Several major news sites had stories about yesterday’s incident. But these weren’t just brief reports of an emergency—journalists were already digging deeper.

“Collapse in central Moscow: negligence or intent?” one headline read.

“Sources in law enforcement report documents indicating the building’s technical condition had raised concerns as far back as two years ago…”

Another article was even worse: “The Cover-Up Scheme: How management companies conceal violations at the cost of human lives.”

It quoted specific figures and names, and even included photos of the very inspection reports Katya had shown me.

That evening I went up to her place.

“Did you read the news?” I asked as she let me in.

“I did. Was it you who sent them everything?”

“It was. And you know what? There’s already a result. Investigators searched the management company this morning. And by evening the director was released under travel restrictions.”

Katya looked energized, but I noticed her hands were trembling slightly.

“Aren’t you scared? What if they figure out it was you who leaked the information?”

“I am,” she admitted. “But I couldn’t stay silent. You understand, those people didn’t just know about your building. They’ve got about twenty more properties in Moscow in the same condition—residential buildings, offices, shopping centers. If we didn’t make noise now, sooner or later someone would get hurt. For real.”

“So what happens to those buildings now?”

“They’ll check them all. Where needed, they’ll shut them down for repairs. In some cases, they may have to relocate people. Yes, it’ll create problems—but people will be alive.”

“You know what struck me the most in all this?” I said. “Not that you found out about the building. But that you decided to warn me. That was risky. What if I thought you were crazy—or worse, told someone you were digging around in other people’s databases?”

Katya shrugged.

“What else could I do? Know someone is walking toward possible death and stay quiet? I’d blame myself for the rest of my life.”

“Not everyone would do that.”

“I don’t know. I think everyone would. It’s just that not everyone has that kind of information.”

At that moment her phone rang. Katya glanced at the screen and frowned.

“Hello?” she answered cautiously. “Yes, it’s me… What? When?.. I see. Thanks for warning me.”

She hung up and looked at me with frightened eyes.

“That was a former colleague from the insurance company. He says they had a search there today too. And he heard a conversation in the smoking area—someone in management mentioned my last name.”

The next few days flew by in tense ожидание.

Katya barely left the apartment, and I regularly went up to see her—sometimes with pastries, sometimes just to check in. In that week we became closer than we had in all the previous months of being neighbors.

On Wednesday evening she opened the door with a radiant face.

“Liz, I’ve got news!” she practically pulled me into the apartment. “The Investigative Committee called me today. Officially. They’re inviting me to give testimony as a witness.”

“Is that good or bad?”

“Great! It means the case is serious if investigators aren’t afraid to involve a hacker. And also… they offered me a job.”

“Where?”

“At the prosecutor’s office. As a computer-crime specialist!” Katya laughed. “Can you imagine? I spent my whole life afraid I’d end up in prison for hacking, and now they’re inviting me to help catch real criminals.”

We celebrated with a bottle of wine I brought from my stash. Snow was falling outside; Katya’s apartment felt cozy despite all the computers. For the first time in months, I felt like I had a real friend.

“And what about our company?” I asked. “Where are we going to work now?”

“You already are. They rented a temporary office on the other side of the city. Oksana told me—she asked your boss.”

Sure enough, the next day Mikhail Petrovich called and gave me the address of the new office.

“Liza, do you happen to have any connections in the press?” he asked at the end of the call. “Because somehow journalists found out all our internal details—even about that project we discussed at a closed meeting.”

“No,” I lied. “What connections would I have in the press?”

A month later the case had grown into something major. Not only was the director of the management company arrested, but several officials who had covered up the violations as well. The city launched a mass inspection of buildings, which uncovered seventeen more properties in emergency condition.

Katya was glowing with happiness. She clearly loved her new job. She told me how she helped investigators untangle computer schemes, how she found hidden documents and traces of digital crimes.

“You know what’s the best part?” she said one evening as we drank tea in her kitchen. “I finally feel like my skills are useful. Before, I hacked systems just because I could. Now I do it to restore justice.”

“And isn’t it scary—working with such serious people?”

“At first it was. Then I realized they’re just regular people, like you and me. They just have a different job. And they truly want criminals to answer for what they’ve done.”

In early spring, the trial took place.

Katya was called as a witness. She was terribly nervous. Of course I went to support her.

The director of the management company received a four-year suspended sentence and a huge fine. His deputy got two years. The officials weren’t acquitted either. And most importantly, the court ordered the company to pay for repairs of all the problematic buildings out of its own funds.

“Justice won,” Katya said as we walked out of the courthouse. “Honestly, I didn’t fully believe it would turn out like this.”

“And I did,” I said. “I believed in you.”

We laughed and headed home.

Ahead of us was ordinary life: work, friends, plans for the future. But now I knew for sure that when something goes wrong, there will always be someone who won’t look away. Sometimes that person lives one floor above you—and is willing to risk their own peace of mind for your safety.

And that, perhaps, is the best thing you can know about the world you live in.