The grinding started again, faster and higher-pitched than before.

The heat from the door was starting to warm the front half of the room.

It was a sickening, metallic heat that carried the scent of scorched insulation.

I reached into my pocket and pulled out my phone, but there was still no signal.

The heavy steel walls of the panic room blocked every cellular tower in the valley.

I looked up at the open duct, wishing I could see Nathan’s face.

I heard a faint scraping sound from deep inside the ventilation shaft.

He was still moving, crawling toward the bypass panel.

Suddenly, a loud crackle broke the silence.

The sound didn’t come from the door or the ceiling.

It came from the old analog intercom speaker mounted on the wall above the safe.

The intercom was supposed to be completely disconnected from the main system.

The speaker hissed with static, a low, buzzing noise that made the girls flinch.

A voice cut through the static, clear and cold.

It was a woman’s voice.

It was Vanessa.

“Nathan, darling,” her voice said, echoing in the small room.