As Marian prepares to embark on a new adventure, Ada and Aurora rush to stop her before it's too late. With Gladys' debut ball fast approaching, the clash between Bertha and Mrs. Astor has consequences for all of New York society. The discovery of a shocking letter changes everything for Peggy. Baudin lays out his double life.

• Julian Fellowes

• Denée Benton
• Christine Baranski
• Cynthia Nixon