| Director | Peter Chan |
|---|---|
| Budget | $20 million |
| Box office | $29.1 million |
The film is set in China in 1917. Liu Jinxi lives with his wife Yu and their two sons Fangzheng and Xiaotian in a village in Yunnan. One day, two robbers show up and attempt to rob a shop that Liu is in. A fight breaks out and Liu kills the robbers – apparently by accident.
Xu Baijiu, a detective sent to investigate the case, discovers that one of the robbers was a formidable fighter, and feels suspicious about how Liu could "accidentally" kill the robber. While the villagers celebrate Liu's heroic deed, Xu performs an autopsy and learns that the robber died of brain haemorrhaging after sustaining a blow to his vagus nerve. After collecting more evidence, Xu realises that Liu is actually a highly skilled martial artist who conceals his talent through misdirection and that Liu is a former member of the 72 Demons, a group of vicious and bloodthirsty warriors. When Xu confronts Liu, the latter admits his past and says that he has reformed.
Xu returns to the county office and obtains an arrest warrant for Liu. After issuing the warrant, the corrupt magistrate informs the Master of the 72 Demons of Liu's whereabouts, hoping to receive a reward. Offended, the Master reveals that Liu is his son and kills the magistrate, after which he sends his henchmen to the village to capture Liu. Liu kills the henchmen, and tells the villagers to take shelter in a fortress.
Using his knowledge of physiology, Xu helps Liu fake his death to fool the 72 Demons. However, the ruse fails, and Liu severs his left arm to signify his cutting of ties with them. Liu then goes home to meet the Master, who has taken Liu's family hostage. The Master agrees to allow Liu to leave the group but Liu's son Xiaotian must take his father's place.
Enraged, Liu attacks the Master with a broadsword but the Master uses qigong to protect himself from the blade. Xu infiltrates the house from underneath the floorboards and uses an acupuncture needle to pierce the Master's heel, weakening his defence. The Master incapacitates Xu and overpowers Liu, but Xu uses another needle to pierce the Master's neck. Just after the Master fatally wounds Xu, he is killed by a bolt of lightning as the needles serve as a lightning rod and earthing wire. With his dying breath, Xu announces the case closed. Liu continues to lead a peaceful life with his family.