Dana (Edana) wakes in the hospital with her left arm amputated. Her husband, Kevin, comes in, and the couple hopes that the police won’t investigate the incident any further.
The trouble began on June 9th, 1976 as Dana and Kevin are moving to a new house in Los Angeles, California. Dana feels dizzy and blacks out, then finds herself at a river where a young boy is drowning. Dana saves the child and gives him CPR, despite the protests of the boy’s mother. The boy’s father comes and points a rifle at Dana, but Dana is transported back to her home before the man can shoot. Kevin crouches over Dana, explaining that she was only gone a few seconds, though Dana is sure she spent minutes saving the boy. Kevin isn’t sure if he believes Dana about where she went, but knows that something very strange is happening.
Dana tries to put the incident behind her, but a few hours later she again feels dizzy and finds herself transported to a bedroom in a wooden house. A boy—who looks like an older version of the boy that Dana saved from the river—is staring at his curtains burning in the corner of the room. Dana throws the curtains out the window, then tries to talk to the boy to find out what is happening. The boy’s name is Rufus, and he remembers almost drowning and then being saved by Dana when he was five. When Rufus repeatedly calls Dana, a black woman, a “nigger,” Dana starts to believe that she is in the pre-Civil War South. According to Rufus, the date is 1815 and they are in Maryland, close to the town of Easton on the Weylin plantation. Dana realizes that she must be traveling through space and time, but she doesn’t understand how this is happening. Dana vaguely remembers an old family Bible that listed the names Rufus Weylin and Alice Greenwood Weylin as the parents of Dana’s great-great-grandmother Hagar Weylin. Dana realizes that she must travel through time and save Rufus each time his life is in danger in order to ensure the survival of her own family line.
To avoid meeting Rufus’s cruel father again, Dana sneaks out of Rufus’s house and heads for Alice’s family cabin in the woods. Rufus gives her directions, saying that Alice is a “free black” and a friend of his. As Dana approaches the cabin, white men ride by and begin to terrorize the black family living there. These patrollers are supposed to ensure order among the slaves, but really just enjoy torturing black people. They whip Alice’s father for leaving the Weylin plantation without a pass and drag him off, then beat Alice’s mother. After they leave, Dana creeps up to the house and secures a safe place to stay for the night. But another patroller waits outside and snatches Dana when she goes out to collect another blanket. Fighting for her life, Dana struggles not to let the patroller rape her and eventually knocks the man unconscious. Terrified that the man will kill her when he wakes, Dana tries to run away but gets too dizzy and blacks out. When Dana wakes, she is back in her home with Kevin. Dana explains that she traveled back in time, and Kevin realizes that she must be traveling to the past whenever Rufus is afraid he will die, and then returning to the present when she herself is afraid of death. The couple put together an emergency bag so that Dana will be ready when this happens again.
Dana and Kevin first met while Dana was working another temp job to fund her lifestyle of writing through the night. Kevin is also a writer, and has a book published. The two bond over their isolation from society and the fact that they have both lost their parents, and they soon begin dating. Others in the office make comments about their interracial relationship, as Kevin is white, but Kevin and Dana pay little attention.
Back in the present, Kevin helps Dana clean herself up after the beating the patroller gave her, but Dana then gets dizzy and returns to Rufus’s time with Kevin in tow. Rufus is sprawled on the ground, having broken his leg falling from a tree as a young slave boy named Nigel watches, unsure how to help. Dana sends Nigel to get Rufus’s father, who comes back with a wagon and a large slave named Luke. They get Rufus back to the house and Rufus’s father, Tom, lets Dana stay with Rufus. Kevin pretends to be Dana’s master in order to avoid questions, and he starts to tutor Rufus while his leg is broken. Dana joins the household, helping the cook Sarah and Sarah’s mute daughter Carrie and reading to Rufus when his strict father and hysterical mother, Margaret, are not around. Dana still has difficulty fitting in, however, because she is educated like a white person though everyone in this time expects her to act like a slave. Eventually, Dana starts teaching Nigel to read as well, but the two are caught in the cookhouse by Tom. Tom drags Dana into the yard and whips her viciously, until she wonders if Tom is trying to kill her. Kevin hears the commotion and comes to the yard, but can’t reach Dana before she transports back to the present.
Kevin and Dana had decided to get married even though their surviving family members did not support an interracial marriage. Now back in the new house that they had bought together, Dana does not feel at home without Kevin there. She carefully tries to wash the lash wounds on her back and recovers for eight days in the present before she is called back to the past. She finds herself in the woods with Rufus, now a young man, who is fighting a young black man while Alice watches. Dana convinces the young man, Isaac, not to kill Rufus, though Rufus raped Alice after Alice married Isaac. Isaac and Alice run away, heading North, while Dana gets Rufus back to the Weylin house. Dana learns that Kevin waited for her a while, but five years have passed since Dana left and Kevin is now in the North. Rufus agrees to let Dana write Kevin a letter, but makes Dana burn a book on slavery and a map of Maryland so that Dana can’t escape on her own.
Four days later, Alice and Isaac are caught by patrollers. Rufus goes to town and buys Alice back, while Isaac is punished horribly and sold to Mississippi. Alice is in terrible shape from the patrollers’ beatings and dog packs, but Dana manages to nurse her back to health and keep her wounds free from infection. As Alice recovers, Rufus forces Dana to convince Alice to become his mistress. Alice hates it, but does so to keep herself safe from more punishment. In Rufus’s room, Alice finds Dana’s letter to Kevin—unsent. Dana decides to run away on her own rather than trust Rufus. She sneaks out and manages to make it past Easton town, but is betrayed by another slave. Tom and Rufus find Dana and bring her back, then whip her soundly. Dana spends a week recovering, then finds out that Tom wrote to Kevin on her behalf. Kevin arrives and he and Dana try to escape the Weylin estate. Unluckily, they meet Rufus on the road and Rufus threatens to shoot first Kevin, then Dana, if they leave. With Rufus’s rifle pointed at her face, Dana gets scared enough that she transports herself and Kevin back to the present.
Kevin struggles to readjust to the present after five years spent in the past trying to help slaves escape while keeping himself alive. He can’t even write anymore, and Dana sees traces of Tom and Rufus in Kevin’s face and voice. After a few hours at home, Dana is transported to the past again and finds Rufus unconscious in a heavy rainstorm. She and Nigel get Rufus back to the house, where Tom puts Dana in charge of healing Rufus from the ague (malaria). Dana does her best with her limited medical knowledge. It has been six years for the Weylins, and Alice has had a child with Rufus named Joe. Dana still desperately waits for her ancestor Hagar to be born so she can be freed of her connection to the Weylin family. After Rufus recovers, Tom has a heart attack and dies. Though there is nothing Dana could do, Rufus blames Dana and sends Dana out to the field for a day of backbreaking work under the harsh overseer’s whip. As an apology, Rufus then assigns Dana to the relatively easy work of being a servant to Margaret, who is now addicted to laudanum. With her education, Rufus also puts Dana in charge of household affairs. He seems to see Alice and Dana as two halves of his wife. Alice has another child, this one finally Hagar, and makes plans to run away as soon as the baby is old enough to withstand the trip. Dana tries to convince Alice to wait and persuade Rufus to officially free Alice’s children, but neither is responsive. Rufus then crosses the line by selling off a slave who had committed the “crime” of speaking to Dana and making Rufus jealous. Stripped of the semblance of control over her life, Dana sends herself back to the present by cutting her own wrists.
Kevin helps Dana get medical attention for her wrists and the two have 15 days of peace to heal and reaffirm their relationship. They have a hard conversation about whether Dana can manage to kill to Rufus if she travels again. Dana believes she can if Rufus attacks her or attempts to rape her. On July 4th, Dana is called back to Rufus. She finds him distraught outside the Weylin house, and learns that Alice has committed suicide by hanging herself in the barn. Rufus punished Alice for trying to run away again by pretending to sell Joe and Hagar, plunging Alice into a deep depression that ended in her death. Dana convinces Rufus to be a true father to Joe and Hagar, even drawing up certificates of freedom for the children when he brings them back to the Weylin plantation from Baltimore. Yet Rufus wants Dana to stay with him and act as a mother to his children. He forces himself on Dana in her room in the attic, and Dana is compelled to get her knife from her emergency bag and stab Rufus. When Rufus dies, Dana is catapulted back to the present, but the place on Dana’s arm where Rufus’s hand was clamped is severed and crushed in the wall of Dana’s house.
After Dana’s amputated arm heals, Kevin and Dana travel to Maryland in the present to find out what happened to the Weylin family. Nigel covered up Rufus’s death with a fire and he and Carrie, now Nigel’s wife, took Joe and Hagar to Baltimore to raise them. Dana knows that she will never find out everything about her family’s past, and Kevin encourages her to look to the future free of Rufus and her other ancestors.