In 1953, two FBI agents are called in to investigate the disappearance of a young White woman in Louisiana. In their pursuit of clues, they stumble across the horrific murder of a Black youth. It soon becomes apparent that the two cases are linked, and solving the murder is the key to unlocking both cases.

But the agents are impeded in their investigation by parties on the both sides of the color line in the victim's hometown of Evangeline, right on the edge of the Louisiana swamplands. The Whites close ranks, seemingly in effort to protect their own; the Black population keeps silent in fear of reprisals and the threat of more violence. And the deeper they dig, the more the agents find that nothing and no one are as they seem...