Concussion stars Will Smith as Dr. Bennet Omalu, the Nigerian neuropathologist who became the National Football League’s public enemy no. 1 when he discovered a new disease crippling many former NFL players — chronic traumatic encephalopathy, a degenerative illness caused by repetitive head trauma.

The film’s first trailer shows Omalu beginning his crusade against the ultra-powerful NFL. (As one character succinctly puts it: “You’re going to war with a corporation that owns a day of the week.”) It also features a series of arresting images that will be familiar to anyone who’s been following CTE’s effects, including a quick shot of an unseen man lifting a pistol — a possible reference to ex-Charger Junior Seau’s well-publicized suicide.

Concussion is set to hit theaters Dec. 25.