Ningtai County's nights remained fairly humid. Though the streets and alleys were kept reasonably clean, it was hard to achieve the spotless perfection of a major metropolitan area.
Especially in places seldom walked by people, like rooftops or the corners of alleyways, there was more dust or grime left behind. Under a car's headlights, an ordinary person could spot faint traces of footprints.
But in Jiang Yuan's eyes, footprints conveyed a wealth of information.
For example, footprints with a faint bluish-green tinge indicated either prolonged walking on grass or contact with moss-like surfaces. Moreover, it had to be nearby; if the person had gone far, the green traces would have long disappeared.
