The book centers on Jane Whittaker, who finds herself on a street corner in downtown Boston with no recollection of her name, her physical features, her personality, or any of the details of her life, albeit being familiar with her surroundings and easily recalling facts such as the formula for the length of a hypotenuse.

Frightened out of her mind, she heads to a hotel, where she spends a couple of days trying to figure out how to proceed.

She decides to go to the local police station, but withholds some key information when she recounts her experience.

Instead of finding rest, however, Jane is overwhelmed by suspicions as she begins to uncover the horrific past that her mind had forgotten.

Along with Dr. Whittaker, a housekeeper named Paula Marinelli - who is obviously loyal to the good doctor - is also taking care of her.