It took Pei Jing six hours to reach Thousand-Marrow Swamp. The ground fell three thousand feet between the pine ridges and the marsh. Snow gave way to warm, heavy air that smelled of rotting ferns and old venom. The last scraps of sleet melted on his hat.
He stopped on a ridge of dry shale and put on his leather breathing mask and horn-rimmed goggles. He had made the spirit-charcoal filter back in Red Mist Market. He checked that it sat snugly against his face, then closed the seals at his throat and wrists. The green fog below him had formed over generations of dead demon beasts. It could eat through bronze given enough time. Neither sect would bring an army down here.
The two flasks at his hips still kept each other in check. He tightened the strap of the Bone Blade and took out the Black Mountain Whetstone. The atlas margin named a mineral test for this fissure. Following the note, he touched a pinch of the test powder to one corner and dipped it into a puddle. The powder hissed. A thin yellow film spread across the water. The plants here were taking up minerals from a hot fissure below the swamp. He was close to the spot marked on the atlas.
