Two New Orleans detectives become embroiled in a centuries-long feud between two secretive factions of vampires while investigating a runaway child's case. Torn between their everyday lives and the dangerous lure of immortality, the detectives must race to destroy the evil Moldero clan.
来自21世纪的项少龙（古天乐 饰）曾意外穿越，并助秦王（林峯 饰）一统天下，这段跨越时空的宿命纠缠将两人紧紧捆绑，两人也成为亦师亦友的情感羁绊。然而，在项少龙归隐田园多年后，未知穿越者却骤然降临，大国基业陷入倾覆危机，秦王不得不求助于早已不问世事的项少龙。面对足以颠覆历史的强敌，他们能否放下芥蒂联手抗敌？那段掺杂着师徒之恩、君臣之畏与知遇之情的情感，又将成为保护彼此的铠甲，还是刺向对方的利刃？
故事据真实事件改编，本片由罗伯逊县警长手机和摄像机的尸体上为素材，制造了一起灵异事件……
