The first thing we hear in this book is that the narrator Dana has had her arm crushed inside one of the walls of her house. We're not quite sure how this could happen, but it seems to be something Dana can't explain to the police or the hospital doctors. And away we go…
It turns out that Dana has the power to travel backward in time. The only problem is that she doesn't get to choose where she goes. Instead, she keeps travelling back to visit her ancestor Rufus Weylin, a young boy living on a Maryland slave plantation in 1815. Oh yeah, and Dana is black, so she's not walking into the friendliest of environments.
Dana quickly realizes that her trips backward in time are provoked by moments when Rufus is in mortal danger. Dana must travel back to save his life so that she can be born more than a hundred years later. The problem is that Dana really doesn't want to save Rufus, because he grows up to be a horrible slave owner himself. He thinks he's a good guy, but this delusion only makes him worse.
As the book unfolds, Dana realizes that she'll need to help Rufus have sex with one of his slaves (named Alice) if Dana ever plans on being born. So she goes through with this plan, even though she hates herself for it. All the while, Rufus whips and beats Dana whenever she disobeys him. He's really pushing his luck because Dana can choose not to save his life at any moment and can leave him for dead.
In the end, Dana decides to take things into her own hands and stabs Rufus to death. Luckily, her ancestor Hagar has already been born by this point, so she can kill Rufus without having to worry about whether she'll stop existing like Marty McFly.
Back in 1976, Dana goes with her husband Kevin to visit the remains of Rufus Weylin's plantation. She reads a newspaper article about how Rufus died in a fire and realizes that one of the slaves must have burned the house down to conceal Dana's murder of Rufus.
Kevin closes the book by saying he's glad Rufus is dead. And that's a wrap.