After leaving graduate school to pursue her dream of becoming a writer, Joanna gets hired as an assistant to Margaret, the stoic and old-fashioned literary agent of J. D. Salinger. Fluctuating between poverty and glamour, she spends her days in a plush, wood-paneled office and her nights in a Brooklyn apartment with her socialist boyfriend. Joanna's main task is processing Salinger's voluminous fan mail, but as she reads the heart-wrenching letters from around the world, she becomes reluctant to send the agency's impersonal standard letter and impulsively begins personalizing the responses. The results are both humorous and moving as Joanna, while using the great writer's voice, begins to discover her own.