影片以一座“没有人心,只有规矩”的人间隐市做背景,隐市规矩自成一体,从而形成了一个全新的生存世界及世界观。全片涵盖了“奇谈”、“悬疑”“药理”等多重元素,围绕 “天赋医师”白青萝(郜思雯饰)同“诡案捕快”拾生(蔡佩池饰)的破案经历,揭开了一件件跌宕起伏扣人心弦的悬案谜底,巧思设置既环环相扣又能发人深省。[Chapter 1: Aconite and the Imp(s)] Officer Hsu is found poisoned and dead in his room one night, next to him stands multiple sing song girls who all look like the long-dead Bai Lin, they chant then vanish. Baffled by the seemingly supernatural nature of the murder, Detective Shi Shen embarks on a journey to the Hidden Town, in hopes that the mysterious practitioner Bai Tsing Luo could help him unearth the truth. [Chapter 2: The night herons long gone] A salt merchant's servant is horrified by the sight of numerous red-eyed mystic herons pecking at her master's body, leaving behind only his bones before they disappear. Soon after arriving at the scene, Detective Shi Shen needs to hurry to Hidden Town for Tsing Luo's cure for a deadly snake venom. Inspired by the case of mystic herons Tsing Luo decides to use the aforementioned birds as remedies. Together with Shi Shen and the newly acquainted Bai Ling, a creature hunter, Tsing Luo sets out to uncover the secrets behind the murder.