The last thing Rebekah Lark remembers is lying on an outdoor swing in her backyard on a clear autumn day in Niwot, Colorado. But now, she awakens in an unfamiliar brownstone in New York City with snow falling heavily. A man enters the room, calls her "Caroline," and serenades her. He acts as though he knows her well. When at last she makes her way to the bathroom and looks into a mirror, she sees that she is someone else.

She presumes this current transmigration is temporary - related to an altered state she experienced as a result of a traumatic brain injury. So, Rebekah plays along, humoring Caroline's six-year-old son, Joel, as well as Leo, the man who thinks she is his wife. Her new family assumes that she, Caroline, is suffering either from transient global amnesia or anterograde amnesia, temporary states of memory loss caused by encephalitis and the brief resulting coma. Rebekah visits Dr. Pinkerton, and the following day undergoes an MRI, which naturally shows no brain damage that might account for Caroline's supposed memory loss. Rebekah's effort to explain her situation to Leo falls on deaf ears. The medical community's sway is powerful, and they convince Leo that his wife is delusional. But, she is the puzzle doctors will never piece. Later the same day, Rebekah calls home and converses with her daughter, Alex, and husband, Connor, under the pretense that she is Rebekah's childhood friend.

Rebekah's eventual surreptitious trip to visit her original family in Colorado ensues in a tug-of-war between the two families. While she is falling in love with her new husband, Leo, in New York, she feels her heart strings pulled by her daughter, Alex, in Colorado who is the only one who knows her mother's true identity.

Despite the initial awkward adjustment to Caroline's more voluptuous body, Rebekah is growing more comfortable as time goes by, as if the body were her own. She can no longer hold Caroline's memories at bay. They come readily to the fore, mingling with her own, possibly supplanting some memories. She forgets what it was like to hold Alex as a baby. The heart has the power to charge memories with meaning. Rebekah loves the people and places that Caroline loves, and while she still longs to be a part of Alex's life, she has little power to change her kismet. Questions remain: Is Rebekah who she thinks she is? If she is not, how does she know what she knows? If she is Rebekah, will she maintain some memories or will Caroline's brain assume control? If we lose our identity, who are we? What power do we give to the medical community to make decisions for us? Why do others fiercely resist when we change? Does the heart as well as brain carry memory? Does Rebekah/Caroline decide to stay in New York or return to Colorado? Read to find out!