In a Louisiana slave plantation run by Confederate soldiers, slaves are treated harshly and not allowed to speak unless spoken to. Those who attempt to escape are killed and their bodies burned in a crematorium. After a failed escape attempt, a black man named Eli watches as his wife is murdered and her body placed in the crematorium. A woman who had been assisting them is later brutally beaten and branded by the general until she submits to being called Eden.

A group of new slaves is brought to the plantation. Among them is a pregnant woman whom the general's daughter Elizabeth names Julia and places in the care of Eden. Julia asks Eden to plan an escape while Eden urges her to keep her head down. That evening during a dinner where Julia and Eden are forced to wait on soldiers in the army, a shy Confederate soldier named Daniel is attracted to Julia and arranges to go to her cabin later. When Julia tries to play on his kindness and asks him to help her, he gets angry and tells her that he is still a Confederate. He beats her for speaking when not spoken to, causing her to miscarry.

After being raped by the general in her cabin, Eden hears a ringing cell phone. In the modern era, a cell phone rings, awakening Eden, who is a renowned sociologist named Dr. Veronica Henley. She is preparing to take a trip to speak and promote her book, which is particularly hard for her because she has to leave her husband Nick and her daughter Kennedi. She has a bizarre online meeting with Elizabeth which leaves her uncomfortable, but she dismisses her feelings and cuts the meeting short.

While in Louisiana on her book tour, she meets acquaintances Dawn and Sarah and agrees to go to dinner with them at a local restaurant. In the meantime, Elizabeth sneaks into her hotel room and steals her lipstick. Intending to go back home early in the morning, Veronica leaves the restaurant in what she believes is her Uber ride but is a car driven by Elizabeth. Elizabeth's husband Jasper knocks Veronica out.

At the plantation, Veronica discovers that Julia has hanged herself. Enraged, she tells Eli that they will escape that night. After being raped by the general again the following evening, she once again sneaks out of her cabin and steals the general's phone. Before she can call for help, she is interrupted by an intoxicated Daniel and another soldier who find the phone but are not suspicious believing it dropped out of the general's bag.

When he is alone, Eli kills Daniel with a hatchet and retrieves the cell phone. As the phone can only be unlocked with facial recognition, Veronica goes back to the cabin to find the general and is surprised to find he is awake. The general attacks both of them and Eli is subsequently killed trying to protect Veronica. She stabs the general with his own bayonet and unlocks the phone, then uses GPS to send her location to her husband. Intending to hide the general in the crematorium, she is interrupted by Jasper. Veronica lures him and another soldier into the crematorium and sets fire to it, leaving the three men to burn to death as she steals the general's horse and rides off.

Elizabeth and another soldier pursue Veronica on horseback and reveals that she handpicked every slave on the plantation except for Veronica, whom she kidnapped at her father's insistence. Veronica knocks Elizabeth off her horse and puts a rope around her neck, dragging her until she hits the base of a Robert E. Lee statue, thereby breaking her neck.