When a humorous script-reader in her New York apartment sees an ad in the Saturday Review of Literature for a bookstore in London that does mail order, she begins a very special correspondence and friendship with Frank Doel, the bookseller who works at Marks & Co., 84 Charing Cross Road.

Two bipolar patients meet in a psychiatric hospital and begin a romance that brings out all of the beauty and horror of their condition.

Alice Howland is a renowned linguistics professor happily married with three grown children. All that begins to change when she strangely starts to forget words and then more. When her doctor diagnoses her with Early-onset Alzheimer's Disease, Alice and her family's lives face a harrowing challenge as this terminal degenerative neurological ailment slowly progresses to an inevitable conclusion they all dread. Along the way, Alice struggles to not only to fight the inner decay, but to make the most of her remaining time to find the love and peace to make simply living worthwhile.