The moment I saw Mrs. Harper’s expression, I knew something was wrong.

It wasn’t the look of someone surprised by a dirty vent.

It was the look of someone who had just realized that a secret hidden for a long time was about to be discovered.

Vincent noticed it too.

“Harper.”

His voice was calm, but there was a warning underneath.

The house manager quickly looked away.

“I’m sorry, Mr. Moretti. I just remembered I have something to do.”

She turned to leave.

But I stopped her.

“Mrs. Harper.”

She froze.

“How long has that smell been there?”

For several seconds, she didn’t answer.

Then she whispered:

“I don’t know.”

A lie.

A small one.

But still a lie.

Vincent noticed.

And that was the first time I saw something change in his expression.

Not anger.

Suspicion.

“Everyone leaves the room,” he said.

Mrs. Harper looked nervous.

“Mr. Moretti—”

“That was not a suggestion.”

Within seconds, only Vincent, the boys, and I remained upstairs.

He looked at the ventilation grate.

“I want the system inspected today.”

I nodded.

“That’s a good start.”

He looked at me.

“You really think something in this house is making them sick?”

“I don’t know.”

That answer surprised him.

“But I know this.”

I pointed toward the vent.

“Your sons spend almost every night here. They breathe this air for hours. If something changed eighteen months ago, we need to know what changed.”

Vincent was silent.

Then he opened Lucas’s bedroom door.

The room was beautiful.

Too beautiful.

Everything was expensive.

The furniture.
The decorations.
The toys.

But the first thing I noticed was not what was there.

It was what was missing.

“Where are their old things?”

Vincent frowned.

“What?”

“Children keep things that make them comfortable.”

I looked around.

“There are almost no personal items.”

He looked confused.

“I redecorated after their mother died.”

The words were quiet.

And suddenly, the timeline became clearer.

Four years ago, Isabella died.

Eighteen months ago, the boys started getting sick.

I walked toward the bookshelf.

A framed photograph sat there.

Vincent and Isabella with the twins when they were younger.

The boys were laughing.

Healthy.

Happy.

I picked up the frame.

“When did the renovation happen?”

Vincent looked at it.

“About two years ago.”

“Who managed it?”

“My assistant hired the contractors.”

“Who approved the materials?”

He didn’t answer immediately.

That silence was enough.

Because in wealthy homes, the people with the most access were rarely strangers.

They were people trusted enough to enter without suspicion.

That evening, I watched Lucas and Leo during dinner.

The reports said they had no appetite.

But I noticed something different.

Lucas pushed away the soup.

Leo barely touched his food.

However, when I served them fresh fruit from the kitchen, both boys ate.

Not much.

But they ate.

Interesting.

“Do you always feel worse after meals?” I asked casually.

The twins looked at each other.

Vincent immediately noticed.

“Boys?”

Leo lowered his spoon.

“Sometimes.”

“Sometimes when?”

The younger twin hesitated.

“When we stay upstairs.”

Vincent’s face changed.

“Why didn’t you tell me?”

Lucas looked down.

“Because everyone says we’re just tired.”

My heart tightened.

Children often stop speaking when adults repeatedly tell them their feelings are not real.

I crouched beside them.

“Tell me everything.”

Lucas looked at me.

“The room smells different at night.”

Vincent stood up.

“What?”

Leo nodded.

“It makes my head hurt.”

A cold feeling moved through me.

Because children had been telling them the truth for months.

And nobody listened.

That night, after the boys fell asleep, Vincent met me in the hallway.

“You think the doctors missed something?”

“I think everyone was looking in the wrong direction.”

He looked at the closed bedroom door.

“Three million dollars.”

His voice was bitter.

“Three million dollars, and I couldn’t find the answer.”

I looked at him.

“You were searching for a disease.”

A pause.

“But maybe you should have been searching for a cause.”

At midnight, the ventilation technician arrived.

After several hours of inspection, he called us upstairs.

His face was serious.

“Mr. Moretti…”

Vincent stepped forward.

“What did you find?”

The technician removed a section of the ventilation panel.

Inside was something unexpected.

Not a broken pipe.

Not mold.

A small device.

Hidden deep inside the system.

Vincent stared at it.

“What is that?”

The technician carefully removed it.

“I don’t know yet.”

I looked at the device.

But there was one detail that made my stomach tighten.

A small engraved mark.

A company logo.

A company that I recognized.

Because it was not a random manufacturer.

It was a company owned by someone who had been close to the Moretti family for years.

And when Vincent saw the logo…

the color disappeared from his face.

Because he knew exactly whose company it was.

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