Claire Foy portrays Margaret, Duchess of Argyll, in this nuanced and emotionally resonant period drama. Her husband, the Duke of Argyll, played here by Paul Bettany, files for divorce after discovering photographic evidence of her infidelity. Without regard for the Duke's own extramarital affairs, the case plays out in front of the media and drags the Duchess' name through the mud, as a shocked society gossips about the details of her sex life and rumours circulate about the identity of her lover. Writer Sarah Phelps avoids repeating the sensationalism of previous accounts, instead producing the humane and complex story of a toxic marriage in which no-one escapes unscathed.