Director Rebecca Carpenter's father, Lewis Carpenter, was a running back for Vince Lombardi's NFL Champion Green Bay Packers. When he dies, her family receives a surprise call from Boston University's brain bank requesting his brain - with shocking results. Lew becomes the 18th NFL player diagnosed postmortem with Chronic Traumatic Encephalopathy (CTE), a degenerative neurocognitive disorder that can cause episodes of rage, social withdrawal, and other unusual behaviors. Carpenter finds herself at ground zero of an unfolding public health controversy and embarks on a three-year odyssey across America to explore the far-reaching implications of this "new" disease in football players.