In 28 days, convicted killer and white supremacist Sam Cayhall will die in the Mississippi gas chamber for the 1967 bombing murders of two small children. While counting down his final days, Sam is visited by a stranger: young, inexperienced law associate Adam Hall, who comes to Parchman Prison to try to save this unrepentant racist and find meaning in his own life. Although his late father changed his family name, Adam is Sam's grandson. As the days and minutes swiftly tick away, Adam uses every legal strategy he knows to win clemency for his grandfather, losing each of these desperate battles in the higher courts. Vehemently opposed to capital punishment, Adam also strongly believes that Sam may be innocent and hopes to uncover the identity of the real bomber. With hope fading each hour, Adam's grueling experience becomes more frightening as he is menacingly shadowed by a mysterious figure who may know the truth behind the crime for which Sam now awaits death in "the chamber."