Just outside London, behind a high stone wall, lies Lake House, a private asylum for genteel women of a delicate nature. In the winter of 1859, Anna Palmer becomes its newest patient. To Anna’s dismay, her new husband has declared her in need of treatment and brought her to this shabby asylum.

     Confused and angry, Anna sets out to prove her sanity, but with her husband and doctors unwilling to listen, her freedom will not be won easily. As the weeks pass, she finds other allies: a visiting physician who believes the new medium of photography may reveal the state of a patient’s mind; a longtime patient named Talitha Batt who seems, to Anna’s surprise, to be as sane as she is; and the proprietor’s bookish daughter, who also yearns to escape.

     Yet the longer Anna remains at Lake House, the more she realizes that—like the ethereal bridge over the asylum’s lake—nothing and no one is quite as it appears. Not her fellow patients, her husband, her family—not even herself. 

     Locked alone in her room, driven by the cruel treatments of the time into the recesses of her own mind, she may discover the answers and the freedom she seeks…or how thin the line between madness and sanity truly is.