Simon (Theo Rossi), a struggling metalworker, becomes increasingly consumed by the rhetoric of Dalton Kirby (Ron Perlman), a provocative radio host whose paranoia and outrage begin warping Simon's view of the world around him. Pushed towards extremism by grief, fear, and influence, Simon reaches a breaking point and takes drastic action – only to realize the true source of the poison consuming him may not be the world around him, but the voice that's been feeding his anger all along.