A British black comedy based on a true scandal that stunned 1920s England. The story centers on neighbors Edith Swan (Olivia Colman) and rowdy Irish migrant Rose Gooding (Jesse Buckley) in the seaside town of Littlehampton. One day, a series of obscene letters begin to target Edith and others, and when suspicion falls on Rose, the women of the town suspect something is amiss and decide to investigate.