In 1960, Jennifer Stirling wakes in the hospital and remembers nothing, not the car accident that put her there, not her wealthy husband, not even her own name. Searching for clues, she finds an impassioned letter, signed simply B, from a man for whom she seemed willing to risk everything. In 2003, journalist Ellie Haworth stumbles upon the letter and becomes obsessed with learning the unknown lovers' fate, hoping it will inspire her own happy ending.