1920s. In the seaside town of Littlehampton, the devout Edith Swan and other local residents begin to receive scandalous letters written in language as eccentric as it is obscene. Suspicion quickly falls on Rose Gooding, an impetuous neighbor who sees her freedom and the custody of her daughter jeopardized by these accusations. As the letters continue to plague the town, police officer Gladys Moss will put her wits to work to solve the mystery and catch the real culprit behind the whole mess.