We can tell from the opening lines of this book that Dana has gone through an experience that has left a deep impression on her. The fact that's she's lost an arm is kind of a giveaway. On top of that, Dana tells us: "And I lost about a year of my life and much of the comfort and security I had not valued until it was gone" (Prologue.2). So it's clear that Dana can no longer be the same woman she used to be. She can never feel comfortable or safe again, at least not in the way she used to. And once we find out about how she's been travelling back in time to American slave times, we get a pretty good sense of why.
Dana begins her story as your average twenty-six year-old woman living in 1976. She doesn't make much money and she's used to living in crummy apartments, but that's about as tough as it gets for her. Things get a whole lot tougher though when she travels back to 1815 Maryland. After a couple of brutal whippings and a day in the cornfields, she realizes that pain is actually the only thing keeping her grounded. As she says at one point, "The pain was a friend. Pain had never been a friend to me before, but now it kept me still. It forced reality on me and kept me sane" (4.2.12).
Apart from the physical pain of working in the fields and being whipped, Dana must also deal with the emotional pain of being a modern black woman making her way in a slave-based culture. She feels constant shame for the way she gives into this culture. She always feels as though she should put up more of a fight whether it gets her whipped or not. Even when she tries to escape the Weylin plantation, she shames herself for not making a cleaner getaway, thinking: "I knew about towns and rivers miles away—and it hadn't done me a damned bit of good! What had Weylin said? That educated didn't mean smart. He had a point" (4.12.42). Even with a hundred and fifty years of historical knowledge to help her, Dana can't find a way to crack the system.
Eventually, other black slaves start shaming Dana for giving into the white masters so easily. Alice is especially insulting when she says, "You run around fetching and carrying for that [white] woman like you love her. And half a day in the fields was all it took" (5.7.24). In other words, the slaves accuse Dana of being a traitor to black people everywhere. She has the ability to put up more of a fight, but she won't because she's afraid of getting hurt.
At the end of the day, Dana will do whatever it takes to keep surviving. She doesn't care what the other slaves think about her. She'll be the personal servant of a woman who hates her (Margaret Weylin) if it means getting through the day without a whipping. She tells us directly:
"She depressed me, bored me, angered me, drove me crazy. But my back healed completely while I was with her" (5.7.19). A fully healed back means more to her than her pride, at least at this point in the book. But then again, everyone has their breaking point…
Dana hits her breaking point after her ancestor Alice has committed suicide. Dana finds out that it was one of Rufus Weylin's lies that made Alice take her life. And when Rufus tries to comfort himself for Alice's loss by raping Dana, Dana grabs a knife and kills him, saying "I pulled the knife free of him somehow, raised it, and brought it down again into his back" (6.4.140). After this, she finally travels to the year 1976 for good, where she and Kevin take a moment to celebrate Rufus' death. That's pretty cold, but an experience like Dana's will do that to you.