I felt my stomach tighten.

Jake was supposed to be here to handle this.

I picked up my phone and dialed Jake’s number.

It rang three times before going to voicemail.

“Jake, call me back immediately,” I whispered into the receiver. “Someone is outside the building.”

I hung up and stared at the screen.

Down below, the pipes began to rattle again, but this time it was different.

It was a rhythmic, deliberate tapping.

Three short taps, three long taps, three short taps.

S.O.S.

Carl was using the old copper pipes to signal someone.

The sound traveled up through the entire building, vibrating through the radiator in my kitchen.

I grabbed a broom from the corner and slammed the handle against the floor.

“Shut up, Carl!” I screamed.

The tapping stopped.

But the silence that followed was even more unsettling.

The man in the wool coat was now walking up the front steps of the building.

I heard the heavy glass lobby door open downstairs.

My phone buzzed in my hand again.

I looked down, expecting a text from Jake.

But it wasn’t Jake.