On the third day of my son, Zeke Murphy's disappearance, I've hacked into the smart AI system belonging to the entire apartment block.

All 202 families in this block are locked up in their respective homes thanks to my ministrations.

After that, I leave my first text message in the residents' group chat. "My son, Zeke Murphy, is in this very building. From now on, I will expose a family's secret every hour. If I can't find Zeke, all of you will go to hell with me."

A CEO of a company with tens of millions of dollars' worth of assets is quick to lash out at me angrily in the group chat.

"Have you gone nuts? Your son's disappearance has nothing to do with us! I order you to stop what you're doing immediately!"

I type out my second text and attach a screenshot of an encrypted financial statement.

"@1502Mr.Cooper, you have 59 minutes left. Here's a friendly reminder to check your overseas bank account. I'd like to see if the tax department is interested in its contents."

I know that Zeke is currently staring at a resident on this very block right now.

Three minutes ago, the residents' group chat was still full of polite concern.

"@801SophiaW, have you found Zeke yet? We're all really worried."

"Just say the word if you need help, Sophia. We'll even raise funds for you."

"Has management checked the surveillance? What did the cops say?"

I leaned against the cold wall, staring at those caring messages on my phone.

My son, Zeke Murphy, had been missing for 72 hours. Three days—the golden window for rescue was slipping away second by second.

According to the police, the cameras showed Zeke for the last time in the first-floor lobby. He waved, as if greeting someone he knew, then skipped happily into the elevator of Block B.

Our building, Grand Summit Residence, was one of the most upscale residential complexes in the city. Security was tight, and one needed facial recognition just to get in or out.

The police checked every visitor record and found nothing, which meant the person who took Zeke had been one of the residents. They went door to door asking questions. Everyone said they hadn't seen him.

The officer had tried to calm me down. "Don't be too worried. We'll expand the search."

Expand the search? My son was right inside this cage of steel and concrete!

I took a deep breath, typed the final line of code into my computer, and hit enter. At once, a low hum spread through the entire building.

Every elevator froze. Every electronic lock snapped shut. The central air stopped running. The network signal was cut off at the physical layer, leaving only a single local network I had built.

The residents' group chat exploded.

"What the hell? Why's the power out?"

"It's not a blackout. All the smart systems are out of control!'

"My door won't open! What the hell is management doing?"

I calmly sent my first message to the group. Peace lasted for a single second before the panic and curses poured in like a flood breaking through a dam.

Mr. Cooper from Unit 1502, a vulgarian who made his money in internet finance, was the first to lash out. "Are you insane? This is illegal detention! I'm calling the police right now!"

I sent out the screenshot I had prepared long ago. It showed his company's internal transaction records. A massive sum of money had been funneled through more than a dozen shell companies before ending up in an offshore tax haven.

I wrote, "Mr. Cooper, feel free to call the police. When they get here, however, they might want to have a chat with you about fraud and tax evasion. The amount involved looks like it's enough for a life sentence."

Mr. Cooper went quiet instantly. The group became silent.

I looked at Zeke's photo on the wall. He was smiling, two little canine teeth peeking out. I said softly to the empty room, "58 minutes left… Mommy will find you, Zeke."

Ten minutes later, the sound of police sirens rose from downstairs.

Officer Holt, leading the team, shouted up through a megaphone, "Stay calm, Sophia Watson! What you're doing is a serious crime! Restore the building systems immediately. We can talk about everything!"

I walked over to the window and pulled it open just a crack. Below, red and blue lights flashed.

Police tape had already been set up. Reporters who had caught wind of the situation swarmed like sharks that smelled blood, trying to break past the line.

I didn't respond to Officer Holt. Instead, I sent a second message to the residents' group chat.

"Everyone, I know you're innocent, and I don't want to hurt anyone. I just want my son, Zeke, to be back. From now on, I need you to do three things.

"First, knock on each other's doors and make sure everything is normal. Second, think carefully—did you see anyone or hear anything unusual between 4:00 pm and 6:00 pm three days ago?

"Finally, send any clues to me, or pass them to Officer Holt downstairs. Remember, you're not just saving my son. You're saving yourselves. After all, no one wants their darkest secrets to become the city's favorite gossip."

That struck a nerve in everyone in the building.

One would ask, "What kind of people lived in the Grand Summit Residence?"

Well, there were entrepreneurs, doctors, lawyers, celebrities, and anyone who wore a polished mask but had skeletons in their closets.

Almost immediately, people in the group chat started tagging each other.

"@1204MatthewW, what's all that noise in your apartment? Are you having renovations?"

"@1808MarienneL, I thought your husband was away on a business trip. I could've sworn I heard a man's voice in your place."

"@everyone, can anyone get into the management office? Sophia can't possibly check every corner alone."

Panic and suspicion spread quickly. The thin veil of civility between neighbors was destroyed by me.

Downstairs, Officer Holt kept pleading patiently, "We understand how you feel, Sophia, but you can't solve this the wrong way! What you're doing is breaking the law!"

I grabbed a Bluetooth speaker, set it by the window, and turned the volume to maximum. "You heard it yourself, Officer Holt. The power of the people is immense. Clues you've spent three days looking for, my neighbours can uncover in an hour.

"And don't try to force your way in or cut the power. The building's fire and gas systems are tied into my network. I don't wish to see any accidents happening."

Officer Holt went silent instantly. A young cop next to him whispered, "Captain Holt, the tech team says the other side is a top-tier expert. The firewall is way too complicated, and it'd at least take six hours to crack."

Six hours? By then, it would be far too late.

Officer Holt picked up the megaphone, his voice hoarse. "Fine. We'll help. We'll search with you. Just don't do anything reckless!"

I stared at the countdown on my screen—35 minutes.

The first hour of the countdown ended.

In the residents' group chat, a dozen or so tips came in, though I could hardly determine their validity. More importantly, none of them pointed to Zeke.

Mr. Cooper sent an angry emoji. "Time's up, Sophia! What the hell do you want now?"

Many others chimed in, convinced I was just baffling. I didn't reply. Instead, I dropped a link in the group. It led to a cloud folder with a single video file.

The thumbnail showed Mr. Cooper and a new female intern from his company… at his very office lounge. It happened when his wife went abroad last week to visit their daughter.

Before long, the whole building could hear the roaring and smashing coming from Unit 1502.

I typed the next message calmly, "@2101DocLynch, you have 59 minutes left."

Dr. Lynch from Unit 2101 was a famous cardiac surgeon in the city, often appearing on TV.

He immediately replied in the group, "Ms. Watson, I don't know why you're targeting me, but I'm happy to cooperate with the police. Everything at my home is normal."

His tone was humble, almost ingenuous.

Downstairs, Officer Holt shouted again, "You're breaking the law, Sophia! Public disclosure of private facts is an invasion of privacy! You're committing a crime!"

I sneered. Why would I care about privacy with a piece of trash who might have killed my son?

I replied to Officer Holt, "If Dr. Lynch's privacy can bring my son back, I'm willing to go to jail. Also, Officer, I suggest you don't focus on me. Check my neighbors, too. Who knows? You might find a killer."

Those words snuffed out the tiny flicker of unity that had just risen in the building. Someone—or maybe a group of people—might have taken Zeke. But who?

My eyes landed on the smallest, most easily overlooked clue.

It came from a tenant in Unit 703, a young woman who said she heard a child playing marbles in the hallway in the afternoon three days ago. The sound was crisp, but intermittent.

Glass marbles were Zeke's favorite toys. I remembered that the day he left, he had a few in his pocket. Which floor did the sound come from?

The young woman wasn't sure. She said it could be from either upstairs or downstairs. The building's soundproofing was excellent, so I surmised that if she could hear it, the source couldn't be far.

I immediately pulled up the hallway cameras for the sixth, seventh, and eighth floors. Just like the police had seen before, there was nothing.

No, wait.

I rewound the footage at my own door, Unit 801, back to three days ago at 4:30 pm. The doormat outside my door was empty. I moved the timeline forward.

At 4:40 pm, a janitress pushed her cart past. At 4:41 pm, she left.

At the edge of my doormat, something new had appeared—a blue glass marble.