Set during the Ming Dynasty, the corrupt official Yan Shifan plots to eliminate his political rival, General Yang Jisheng, by deploying a ruthless assassin organization known as the "Thirteen Deadly Zodiacs" to wipe out the entire Yang clan. Zhen Zhaoren, the group's most lethal killer, suffers from a dual personality—a righteous man by day and a cold-blooded executioner controlled by a hypnotic curse at night. When Zhaoren's conscience awakens during a brutal mission, he defects from the organization and goes on the run. Aided by Yang Yunqing, the heroic survivor of the Yang family, Zhaoren must break his mental shackles, confront his former comrades, and put an end to the tyrannical rule of the Yan faction.