Dr. Bennet Omalu, a forensic pathologist working in Pittsburgh, stumbles upon an unusual pattern of brain damage while conducting the autopsy of Mike Webster, a former NFL football player who died under mysterious circumstances. Omalu's discovery leads him to suspect that the repeated head traumas sustained in football could lead to severe cognitive decline in the form of a disease he calls Chronic Traumatic Encephalopathy (CTE). As he delves deeper into other cases of former NFL players with similar symptoms and untimely deaths, his research begins to suggest a disturbing link between football-related head injuries and long-term neurological damage.

Driven by a commitment to truth and the scientific method, Omalu publishes his findings, hoping to shed light on the issue and protect players. However, his work quickly faces fierce opposition from the NFL, which has a vested interest in downplaying the risks associated with America's beloved sport. Omalu's resolve is tested as he encounters personal and professional backlash. He must navigate the complicated intersection of sports, medicine, and business, while trying to maintain the integrity of his research amid efforts to discredit him. Despite the mounting challenges, Omalu persists, driven by his duty to tell the truth and prevent further harm to players who risk their lives on the field.