Warden Bernadine Williams, Alfre Woodard oversees the execution of inmate Victor Jimenez, with the prison chaplain David Kendricks, Michael O'Neill at his side. The attending medical officer falters, unable to locate a usable arm vein, and panic begins to rise. Bernadine grants permission to access the femoral vein. The procedure spirals out of control as Victor writhes on the table before his heart finally stops.
Anthony Woods, Aldis Hodge is a quiet man on death row who insists on his innocence and refuses to speak to Bernadine when she visits his cell. Bernadine is well acquainted with Anthony's lawyer, Marty Lumetta, Richard Schiff, who has fought for seven years to win his client’s release. From Marty, she learns that Anthony has exhausted his final appeal, and she begins to prepare for the execution. At home, Bernadine struggles with insomnia and recurring nightmares.
Behind the calm exterior, Bernadine struggles emotionally, drinking heavily after work and clashing with her husband, Jonathan Williams, Wendell Pierce. After an argument on their wedding anniversary, Jonathan leaves and checks into a motel.
Anthony receives a letter from his former girlfriend Evette Wilkinson, Danielle Brooks, telling him that he has fathered a child. She explains that she hid the pregnancy from him and raised their son with another man because it offered a better life than having a father on death row. She offers to let Anthony meet his son before the execution.
With all court options exhausted, Marty files for clemency and appears on television while continuing to visit Anthony. Bernadine visits Chaplain Kendricks and urges him not to give up on Anthony. Jonathan returns home and they reconcile, though Bernadine keeps her emotions to herself.
On the day of the execution, Anthony waits for Evette and his son, but they do not show up. Bernadine leaves voicemails for Evette, but there is no reply. As Marty and Chaplain Kendricks offer solace, the governor’s office calls to say clemency has been denied. Anthony is escorted to the execution room and strapped to the table. In his final statement, he addresses Mr. and Mrs. Collins, the parents of the man he was convicted of murdering, expresses sorrow for their loss, reaffirms his innocence, and thanks Marty and Chaplain Kendricks for their help. Bernadine weeps as she watches him die.