During the Republic of China era, whenever thick fog blanketed the area and ethereal sounds echoed, mysterious treasures were said to appear in the ancient tombs behind Bashu Village in Sichuan. A group of travelers gathered in Bashu Village, each intent on claiming the village’s treasures for themselves. Unbeknownst to them, an unseen presence was silently watching their every move. When these villains finally unearthed the treasure, they met gruesome deaths one after another near the tomb...

改编自小说《南宋第一卧底》，讲述了南宋年间，钱塘县捕头沈墨(唐禹哲饰)被迫卷入一宗鬼樊楼血案，从而一步步揭开一个不为人知的惊天秘密的故事。

该剧讲述了心怀正义、一心为民的刺客郑轲为了刺杀民间传闻中荒淫无度的皇帝，不小心与公主齐婉儿互换身体，在完成任务的过程中，俩人互生好感，期间发现一切都是由奸臣设计陷害皇帝，于是毅然帮助皇上铲除奸佞，并与公主喜结连理的故事。