In an alternate near future, an underground fight club and a criminal organization known as Skizm achieved massive popularity by live-streaming real death matches between criminals and psychos. Ordinary computer programmer Miles Lee Harris, who gets his kicks by trolling online trolls, logs into Skizm’s forum to insult viewers who turn murder into entertainment. Riktor, the criminal kingpin and psychopath who runs Skizm, breaks into Miles’ apartment with his henchmen Dane, Effie, and Fuckface. After being beaten and drugged, Miles wakes up to find guns bloodily bolted into both of his hands. Miles learns that he has been forced to participate in Skizm by being pitted against Nix, the game’s deadliest and craziest killer; she wants out but not after her last opponent, Miles.
Nix tracks down Miles, who tries to explain his unwanted predicament, but Nix merely shoots up his apartment; Miles escapes outside. After unsuccessfully attempting to recruit help from the police, Miles made it to the park for a rendezvous with his artist ex-girlfriend Nova Alexander, who tells Miles she doesn’t want to get back together. When Miles reveals what is happening to him, Nova flees in fright. Nova reports the situation to Detective Degraves. Degraves has his partner Stanton hack Nova’s phone so they can track Miles. Miles gets temporary help from a vagrant named Glenjamin. Miles then goes to the office where he works so his friend Hadley can hack the Skizm tracking malware on his phone.
Miles finally gets assertive by angrily pulling his guns after his continually condescending boss Zander insults him. Nix then suddenly guns down Zander and starts shooting up the office. Miles escapes in a stolen car and Nix chases him on a motorcycle. Following a face-off where he again fails to reason with Nix, Miles calls Nova but sees Riktor kidnapping her. Miles calls 911 and leaves his phone in a junkyard to summon the police. He then inadvertently interrupts a drug deal between two rival gangs. Nix shows up and starts gunning down thugs while trying to get to Miles.
The cops arrive and arrest Miles. While transporting him, Degraves and Stanton explain their plan to use Miles as bait to lure Nix, whom they’ve been trying to capture for years. Degraves reveals Nix is his daughter. Nix was driven criminally insane after Riktor took revenge on Degraves for taking down Riktor’s gang by blowing up his family’s van. Degraves managed to save Nix, but his wife and son died. Stanton reveals he is a mole working for Riktor when he shoots Degraves in the head. Stanton plays a video message in which Riktor explains that Miles has 30 minutes to kill Nix or else he will kill Nova. Miles recovers his phone from Degraves’ body. While coercing a gaming café patron into hacking Nova’s phone to retrieve her location, Miles learns the Skizm communities dubbed him ‘Guns Akimbo’ as he has become the most popular player ever. Miles arrives at Nova’s supposed location to find Riktor waiting. Riktor taunts Miles by dumping Hadley’s dead body before driving away.
Miles manages to secretly meet with Nix and tells her that Riktor murdered her father and kidnapped his ex-girlfriend. In her rage and desire for revenge, Nix agrees to a plan where they successfully stage a scene for Skizm’s broadcast camera drones. She seemingly guns down Miles, who is actually wearing a bulletproof vest he removed from Degraves. Henchmen recover Miles’ body and transport him to Riktor’s Skizm hideout. Nix joins Miles as they take down Riktor’s henchmen, including Dane and Effie. Nix sacrifices herself by detonating a suicide vest that blows up Fuckface and the rest of Riktor’s men so Miles can survive. Riktor executes Stanton while making his way to the rooftop with Nova.
At the rooftop, Miles tries to shoot Riktor but wasting his last bullet and Riktor shoots at Miles. Determining the end Riktor. Miles pulls himself and fiercely charges at Riktor while Riktor keeps shooting at Miles. Nova breaks from his bond and temporary stun Riktor for Miles to rush at him and pummel him with his twin pistols. Riktor gloats that he makes Miles from a nobody to celebrity only for Miles to push him over the edge of the building. While hanging on with his life, Riktor then reveals that he has successfully made Skizm, a worldwide franchise so killing him won't stop the program. Miles then shoves Nix's middle finger into his mouth hit both Riktor's hands in which he loses the grip and falls to his doom. After Riktor dies, Miles starts to collapse from massive blood loss while imagining a romantic reunion with Nova. However, Nova actually becomes frightened and goes into shock after seeing what Miles is turning into.
Some time later, Miles is scarred from his injuries and while sitting in his car, he opens a file. He discovers a comic book written by Nova and learns that she is promoting Miles as a popular hero by writing a comic book based on their story. With Skizm spreading worldwide under new leaderships, Miles commits himself to do everything in his power to destroy the entire criminal organization.