Kan Fung, Andy On Chi-Kit, escapes from the organization that granted him his superhuman abilities and seeks a geneticist who can cure him. He decides to use his powers for the greater good, adopting the moniker Black Mask.
Lang, Scott Adkins, a high-ranking member of that organization, is hired to find and kill Black Mask, setting up a tense cat-and-mouse dynamic between two powerfully enhanced figures.
King, Jon Polito, a wrestling promoter, prepares for a major event featuring his top wrestlers: Claw [Rob Szatkowski], Iguana [Andrew Bryniarski], Chameleon [Traci Lords], Snake [Robert Allen Mukes], and Wolf [Oris Erhuero]. The show becomes personal when Iguana attacks Ross, provoking Black Mask to intervene as chaos erupts and the crowd realizes the promoters’ prizefighters are more than mere athletes.
Iguana, a transformed hybrid, pummels Ross and triggers a dramatic chase to a nearby tower. In a fateful moment, Black Mask attempts to save Iguana, only for Iguana to declare that he is not a monster and then slip from Black Mask’s grip, plummeting to his death. Chameleon, Iguana’s partner, who can blend into surroundings, watches as Iguana’s remains revert to human form, deepening the mystery for everyone involved.
It’s revealed that the wrestlers were experimented on by Dr. Moloch, who injected them with animal DNA to heighten their fighting abilities. The injected DNA grants the wrestlers the power to morph into animal-hybrid forms, and with vengeance on their minds, they set out to track Black Mask down. Chameleon begins moving naked to stay fully invisible, a stark and unsettling image as she stalks her target.
Meanwhile, Black Mask tracks down Dr. Marco Leung, a geneticist who might cure him, and reaches out through anonymous calls to seek her help. He also befriends Raymond, Ross’s young son, who looks up to both his father and Black Mask, creating a fragile alliance that could be crucial if a cure is ever found. During the investigation into the wrestlers, Black Mask’s path collides with an invisible Chameleon, and an encounter leads to him being injected with animal DNA by Moloch, transforming him into a tiger-hybrid with newfound power to fend off his stalker.
Seeking relief, Black Mask locates Dr. Leung and warns her about the injected DNA, requesting her assistance. Dr. Leung identifies a chemical component that might cure the tiger DNA, and Black Mask secretly retrieves the necessary chemical during another confrontation with the wrestlers. After taking the cure, Black Mask is purged of the tiger DNA, but a violent reaction erupts, leaving him dazed and wandering the city in a daze.
Cornered by an invisible Chameleon, whose upper body occasionally brightens and fades, Black Mask reveals Iguana’s death was not accidental and that he had truly tried to help him. He also explains to Chameleon that she is losing control of her body and that her invisibility will fade unless she acts. Remorseful and fearing disappearance, Chameleon becomes semi-visible and withdraws, a moment that underscores the tragic cost of their powers.
In a climactic confrontation the next day, Lang incapacitates Moloch and plants a citywide bomb capable of altering DNA. Snake is killed by Black Mask, and Wolf is accidentally killed by Thorn, who misidentifies him in the dark. General Troy, Lang’s loyal subordinate, battles Black Mask and then pursues Dr. Leung, only to be crushed by falling pipes. Chameleon, still unclothed and completely invisible, ambushes Thorn, swipes the bomb from him, and hands it to Black Mask. After a tense scuffle with Thorn again, Chameleon and Thorn are left hanging from a support beam high in the arena, and, recalling Iguana’s death, Chameleon’s upper body reappears briefly. She then fades again, vowing she will not disappear and pushing Thorn’s arm off the beam, sending both of them to their deaths. Even as she falls, Chameleon’s head and shoulders briefly reappear in bronze before stabilizing.
Finally, Lang closes in on Black Mask. Although Lang initially tightens his grip, Black Mask ultimately overpowers him and detonates the threat, preventing the city from being rewritten by the bomb. The following day, Dr. Leung receives a call from Kan Fung and leaves the lab, riding away on Kan’s motorcycle, a quiet cue that she has succeeded in curing him of his original superhuman abilities.
