Detective Tyler Burke (Roger Cross) and his two men infiltrate the house of a drug dealer George Freemont, with whom he had been secretly collaborating to sell police-confiscated narcotics. They ask him for Freemont’s proof of their collaboration. They destroy Freemont’s laptop, and Burke shoots Freemont after making it look like Freemont shot first.
Detective John Shaw (Dean Ambrose) returns to active duty at his precinct after the death of his partner, Ray Jones, in which Shaw was shot and sidelined with post traumatic stress disorder. He is met by his supervisor, Captain Matthews, recent police academy graduate Officer Jenny Taylor (Sarah Smyth) and lastly Detective Burke, who is being hailed for his ‘bust’ of Freemont.
Unknown to Burke, Freemont had made a backup containing the incriminating evidence that is in the form of a flash drive in the shape of a credit card, which is found during Freemont’s autopsy and delivered to Evidence by Taylor. Shaw reads the incident report of the Freemont bust and retrieves the flash drive from Evidence. At the same time, Burke, at his home, receives a call from Taylor regarding the flash drive. Burke deduces that the flash drive contains the evidence and quickly heads to the precinct. Discovering the content of the flash drive, Shaw heads to Matthews’ office. Burke receives word from Officer Meeks, one of his corrupt colleagues, that Shaw had already checked out the flash drive, but misses Shaw though both men shared the same elevator. Burke is unable to intercept Shaw and triggers the fire alarm so that everyone (except he and his fellow corrupt cops) can evacuate the building and find Shaw easily. Once the building is evacuated, Officer Darrow (Lochlyn Munro) takes over security control to monitor Shaw’s whereabouts via CCTV and also initiates a total lockdown of the building, disabling all the phone communication, computer networks as well as jamming cell phone signals. Shaw, unable to find Matthews at her office, had ducked into a stairwell to call her on his cell, but is cut off by the lockdown.
Shaw, knowing that he is now being hunted, ambushes Meeks but is surprised by Burke, Shaw uses Meeks as a shield, but Meeks is shot anyway by Burke. Shaw and Meeks duck into an elevator, but Meeks dies soon after. Burke radios Darrow to shut down the elevators, but Shaw manages to escape.
Shaw next runs into Taylor, who had been accidentally locked in. She sees Meeks’ blood on Shaw and refuses to trust him, forcing him to draw his gun on her. He confiscated her taser and leaves her with a warning to hide until the lockdown is over. Matthews arrives and hails Burke over walkie talkie. Burke takes the opportunity to frame Shaw, directly blaming him for Meeks’ death and assuring Matthews that he will handle Shaw. Shaw then goes into the motor pool where is spotted by Darrow on the camera. In the ensuring pursuit, Shaw is hit by the bullet to his arm while attempting to flee in an unmarked police car, but manages to elude his pursuers.