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 Riktor requires she kill one last opponent, Miles.
Nix tracks Miles’ phone, he tries to reason with Nix but she intends to kill him. Miles distracts her and she shoots up his apartment, as he falls down the fire escape. After unsuccessfully attempting to recruit help from the police, Miles makes it to the park to meet 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. Zander is shot in the head by Nix, who 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 thirty 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, Riktor keeps shooting Miles, but the latter determinedly charges at Riktor and ultimately throws him off the roof to his death, not before Riktor tells Miles that Skizm has spread worldwide and is becoming a global franchise. 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.