He flicked the lighter on and offered her a hand to help her finish her descent. It was hard to see in the tunnel, the air so heavy with sewer water that it made it difficult to breathe. He ripped off the corner of his shirt and handed it to her, hoping that it didn't smell as bad as the water they were standing in.
"Put it over your fucking face," Zach muttered. "Don't know how bad the gases might get. Or what's down here." He did the same, the shirt now ripped and ragged along the edges. Holding the cloth to mouth and nose, he began to strike through the darkness, water at ankle height as he held the lighter out as high as he could to show the way through the sewers.
The walls of the tunnels were grey and almost impossible to distinguish from one another beyond the occasional line of lime left by the acrid waters, wavering and dipping like old mosaics where the cracks of concrete twined, puzzles beneath the heart of the city where it still throbbed, pulsing echoes of machinery from beyond the wall, a mechanical heart occasionally forcing the water at ankle and calf to lift higher - lift, then fall, like breathing or a sigh.