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.

My heart started pounding.

This marble was the first piece of physical evidence since Zeke disappeared. Why was it on my doorstep? Had he left it himself as a signal, or was the kidnapper taunting me?

The janitress.

Immediately, I tagged the property manager in the residents' group chat. "Send me the full list and photos of all cleaning staff on duty recently. ASAP!"

The property manager, clearly terrified, didn't delay. A few seconds later, a list appeared. The photo showed a janitress named Jane Miller, in her 50s, with a face that looked honest and reliable.

I posted the screenshot to the group. "@everyone, does anyone know Ms. Miller? Which floors does she clean? Where is she now?"

Replies came in almost instantly.

"Ms. Miller is very nice and hardworking."

"She's responsible for the high-rise section, floors 12 to 22."

"I don't think she came in today."

A foreboding hit me immediately. I switched screens and began tracking into the citywide traffic monitoring system.

My husband, Sam Murphy, was a cybersecurity architect. Over the years, just by being around him, I had picked up a few tricks myself. The tools he left on our home computer became top-tier weapons in their own right.

I typed in Jane's ID number from the property manager. Almost instantly, I pinpointed her address, a rundown urban village.

Meanwhile, Officer Holt was also taking action. "Sophia, we've already sent people to find this janitress. Don't get worked up—it could just be a coincidence."

Coincidence? I didn't think so.

I tracked the police cars heading toward the village while keeping a close eye on the residents' group chat. The countdown for the second hour had just ten minutes left.

Dr. Lynch suddenly posted a long message in the group.

"Ms. Watson, I understand a mother's feelings. How about this? I'm willing to offer one million as a reward for anyone who provides a lead on your boy. As long as it helps find the kid, I'll pay.

"But please, don't do anything that could harm anyone else."

His words instantly won him favor with many neighbors.

"Dr. Lynch, you're such a good person."

"See that, Sophia? Dr. Lynch is offering you a better solution. What more do you want?"

Would he really be this generous if he knew I didn't have leverage over him?

I ignored him and spoke to my computer instead. "Sam, are you ready on your end?"

From the speakers came Sam's tired but steady voice. "All set. Just say when."

He was in Alvoria, across the vast ocean. He was my backup, my last card to play.

The countdown entered its final minute.

In the group, everyone held their breath, waiting to see what shocking scandal would be exposed about Dr. Lynch. He was so nervous that he spammed the group with countless begging emojis.

Time was up. I didn't send any links, just a message. "@2101DocLynch, your wife just threw all three of your laptops and hard drives out of the window."

A chorus of gasps rose from downstairs, followed by the thunderous crash of falling objects. Then came the hysterical roar from Dr. Lunch's apartment, Unit 2101.

I closed the residents' group chat. I knew he was finished. The records of all the illegal organ transplants he had conducted over the years were enough to put him behind bars for life.

Finally, Officer Holt called. His voice was full of shock and disbelief. "Hey, Sophia. We, uh… We found the cleaning lady at home. She had hanged herself."