With more of her life behind her than ahead, Margaret Braverman, a physicist teaching at a small college, cannot help but regret the things she never quite got right. Most important among them was the tragic ending of her romance with her brilliant colleague Frank, something she has never gotten over. And, of course, it would be glorious to get even with that mean-spirited, conceited, womanizing Caleb Winter. After years of experimentation in the back room of her lab, Margaret has finally built a time machine. The key, she discovered, is in teleporting not the body but the mind. And so, at 5:03 p.m. on May 3, 2012, Margaret teleports her mind to her 1987 self. She is able to see and hear but cannot move a muscle. Will she be able to change the future?