Mitzi stood in the doorway for a moment, her eyes searching for movement in the darkness. Then, with a deep breath, she stepped over the threshold and into the gloom. The night vision turned on with a quiet click, and the stairs and walls suddenly stood out in a sickly green glow.

Something had damaged the inside of the stone stairwell. Holes had been gorged into the walls, and several steps had their ends chipped off. Some dark liquid had dried on the walls, and Mitzi moved past it quickly.

The steps seemed to go on forever. When they finally reached what Mitzi had taken for the end, it turned out to be only a landing, and the stairs continued to their right.

“Jeeze,” Mitzi muttered, grateful that her suit was putting in most of the effort for her. “You’d have to be fit if you lived here.”

“They had elevators for the lazy people,” Nic said. She could hear faint typing through the headset and wondered if he was still looking for heat spots. “But they wouldn’t work anymore, of course.”

There was more dried liquid on the ground, painting a dark streak down the steps. Something large had been dragged that direction. Mitzi kept close to the edge of the stairs to avoid stepping on it and sped up, eager to reach the end of the climb. “We must be more than a level down by now.”

“Pretty much. Most surface buildings had basements, and below the basements were the pipes.”

“The oil pipes?” Skye asked, her voice filled with wonder.

“That’s right. Carrying crude and refined oil to different sections. It’ll all burn with enough heat, of course. But you’re going below that, past the first underground floor and into the second underground floor. That’s where the reactor is. If you can make a clear run of it, you should be able to set the detonator and make it back to the surface in less than ten minutes.”

“I like the sound of that.” The stairwell ended, and Mitzi hesitated. Ahead of her stretched a long hallway with multiple offshoots and several doors. Every light had been broken, and shards of glass littered the ground. One door several meters on had been torn off its hinges.

“Turn left,” Nic instructed. “There’s another stairwell to take you down to the second underground floor.”

Mitzi turned then hesitated. She could see the opening to the second flight of stairs, strangely shaped in the harsh green light, but her instincts were screaming at her to back away.

“Nic?” She was whispering, even though she knew sound couldn’t easily escape the suit. “I think I can hear something. Is there any way to enhance the external audio?”

“Sure thing, doll. Hold on a second.”

Mitzi felt her team shift uneasily behind her. There was a quiet click, then the sounds of the hallway were played into her helmet, magnified two-fold, and the noise that had disturbed her was suddenly much clearer: dripping water. It was infrequent and distant, but the way it echoed from the lightless tunnel set Mitzi’s teeth on edge. “Is there another stairwell?”