Kai Jin, a young Chinatown chef in present day San Francisco, becomes entangled with the Chinese Triad's pursuit of deadly ancient powers known as the "Wu Xing.
Kai (Iko Uwais), Lu Xin (Lewis Tan) and Tommy (Lawrence Kao) travel to Bangkok to hunt down the killer of Tommy's sister Jenny, having found on her body an ancient talisman that leads them to Thailand (Tommy tracked the metal on the talisman to Bangkok).Kai is a Wu Assassin. Kai was visited by a 10000-year-old warrior spirit brought back to Earth. The spirit gave her powers to Kai, making him the current Wu Assassin.
Upon their arrival in Bangkok, the trio is attacked by 2 Jiangshi (is a type of a Vampiric monster present in the Chinese folklore. It is known to be a dead creature that sucks out the living force of humans), whom they manage to fight off.
There, biotech billionaire William Pan (Jason Tobin) approaches them, requesting that they bring to him his twin sister, underworld boss Ku An Qi (Rhatha Phongam), a Jiangshi (A Chi vampire) and Queen of the Bangkok underworld, who has been consuming massive amounts of Chi to expand her supernatural powers in order to take over the world.Ku had gone looking to attack Kai, the current Wu Assassin to eliminate him, but Jenny intervened. She fought valiantly but died.
William explains to them that he and Ku are descendants of Pangu, the being who had shaped the universe out of nothingness and created everything. Pangu then ascended to become a God and the Dau sent the first Wu Assassin to terminate him.
The Pangu was killed by the first Wu Assassin after he went mad with power and whose essence is now contained within two talismans: one in the possession of William and the other Tommy had found on Jenny, which had formerly belonged to Ku. William tells them that Ku had killed Jenny while searching for Kai, the current Wu Assassin, but lost her talisman in a fight with her, and that now he can use both talismans to Depower Ku and restore order to the universe. The trio agree to help William.William informs the trio that Ku would be attending a meeting with the 5 Triad bosses in 5 days' time. William says that his powers extend to the mind while Ku's powers extend to the body.
Joined by Tommy's friend Preeya (Francesca Corney), the group plan to kidnap Ku from a meeting with the city's Triad bosses at the Vie Hotel. Preeya and Tommy distract security with a fake infiltration attempt, allowing Lu Xin and Kai to pass through undetected.Interpol was observing the events at the hotel, and they see that the hotel cameras have been jammed after Preeya activates a hidden Jammer.Ku enters the meeting and uses her powers to absorb the Chi of the Triad bosses. Agent Zama enters the hotel and finds Lu Xin and Kai at the Triad bosses room, after Ku had already left the hotel.Ku uses mind control to make everyone in the building attack the group, while Kai is ambushed by long-time foe Zan (JuJu Chan), who is also working for Ku.They escape with the help of Zama (Pearl Thusi), an Interpol agent also after Ku and is also Lu Xin's former lover.
The group escapes the hotel in Zama's van but is chased through the city by Ku's armies. The group is forced into hand-to-hand combat at a local market, and they manage to fight them off.The group eventually make their way to the safety of Preeya's village, where the village shaman tells them that William is actually secretly working with Ku to attempt to reform Pangu so they can remake the world in their image. To do so, they require both talisman and Kai's Chi (the Chi of the Wu assassin, the one who split the Pangu in the first place).
That night Zama has sex with Lu Xin. Preeya hooks up with Tommy again. Preeya reveals she lost her family in the flood more than 10 years ago. She was helpless.William and Ku persuade Preeya to steal the talisman from Tommy by offering to bring her dead family back to life, and she uses it to absorb some of Kai's Chi. The village is attacked by Ku's men but Kai, Lu Xin, Tommy and Zama escape (The Shaman Chatree tells Kai to stop Pangu from reforming and offers to stop Ku's forces by himself. Chatree is chopped down).
The group tracks down William and Ku to an archaeological dig site where the first Wu Assassin fought Pangu. A remorseful Preeya helps Tommy and Zama defeat Ku, while Kai fights and kills Zan.However, with Kai's Chi William manages to reform Pangu, who takes over his body and pits a mind-controlled Lu Xin against Kai. Kai is able to snap him out of it and the two defeat Pangu, trapping a dispossessed William underground.
The group celebrates their victory with a day at the beach, but Kai tells them that he has to battle a necromancer next.
