A 1920s English seaside town bears witness to a dark, absurd scandal in this riotous mystery comedy. Based on a stranger-than-fiction true story, "Wicked Little Letters" follows two neighbours: deeply-conservative local Edith Swan (Olivia Colman) and rowdy Irish migrant Rose Gooding (Jessie Buckley). When Edith and fellow residents start to receive wicked letters full of unintentionally hilarious profanities, foul-mouthed Rose is charged with the crime. The anonymous letters prompt a national uproar, and a trial ensues. However, as the town's women, led by Police Officer Gladys Moss (Anjana Vasan), begin to investigate the crime themselves, they suspect that something is amiss and Rose might not be the culprit after all.