Martial arts master Shangguan Xingyu encountered a murder while pursuing a black-clad figure. The victim's bizarre state aroused his curiosity. Little did he know this marked the beginning of a string of killings—a locked-room murder followed by a massacre at a medical clinic. Clues from each case pointed to the "Butterfly Killer," plunging the Dali Temple investigators into a labyrinth of mystery while his junior sister Mo Zhaoyan found herself in grave danger. Entrusted by the Dali Temple to investigate, Shangguan Xingyu forms a task force with the Southern Frontier's extraordinary woman and the Junior Minister of the Dali Temple. Can they cut through the layers of mystery, break the deadlock, and uncover the true culprit?