“No one would suspect murder if he simply faded away.”

The phone in Lorenzo’s hand vibrated again, the screen flashing with a second message from the unknown number.

I leaned closer to read the words over his shoulder.

*The vents are closing. You have five minutes of air.*

We both looked up at the ceiling.

A heavy, metallic thud echoed through the ductwork as the intake dampers sealed shut.

The small room suddenly felt much smaller, the air growing thick and still.

“Who is sending these messages?” I asked, my heart hammering against my ribs.

“Someone who knows the security protocols,” Lorenzo said.

He stepped toward the heavy, steel-plated door and pushed against it.

It did not budge.

The electronic keypad on the outside was completely dark, its backup battery disabled.

“The central security grid has been completely bypassed,” Lorenzo said.

“This is not a simple power failure.”

“Only three people have the physical bypass keys to this wing.”

“Myself, the chief of security, and Mrs. Bellamy.”

He shone the phone light around the perimeter of the room, searching the corners.