Mamie Till Mobley, a young mother living a simple life in Chicago, begrudgingly lets her adventurous 14-year-old son, Emmett, go on vacation with his great uncle and cousins to Mississippi. Days after his arrival, tragedy strikes and Mamie is faced with a mother's worst nightmare when her son goes missing.

After her son's body is recovered in Mississippi, Mamie insists on having a public wake with an open casket to ensure that he did not die in vain. The case becomes national news, which puts pressure on Mississippi officials to do the unthinkable—go to trial.