George Russell has found his shooter. The Gilded Age season 4 opens with Downton Abbey creator Julian Fellowes' period drama returning to New York, where George (Morgan Spector) hired Pinkerton detectives as bodyguards and to track down the man who shot and nearly killed him in season 3. The Pinkertons have located an unidentified man living in the tenements with a woman George recognizes.
George remains unstable since the shooting. He is temperamental, refuses to eat, and will not live with his wife Bertha (Carrie Coon). His son Larry (Harry Richardson) observes that his father is "not himself." George faces another crisis: his business rival John D. Rockefeller and Standard Oil are pricing out Russell Industries, threatening ruin for the family.
In London, Gladys Russell (Taissa Farmiga) gave birth to a boy, the new Marquess of Sidmouth, but nearly died from hemorrhaging. Her physician saved her life by removing her uterus, preventing future pregnancies. Bertha and the Duke of Buckingham (Ben Lamb) decided to keep this secret from Gladys to "protect" her.
Back in New York, Oscar Van Rhijn (Blake Ritson) married Enid Winterton (Kelly Curran), a woman of means who knows Oscar is gay and supports him living as he chooses. Agnes Van Rhijn (Christine Baranski) discovered Enid was once Bertha's lady's maid, but Enid offered to finance Agnes' upcoming dinner for President Grover Cleveland (Jim Gaffigan).
Marian Brook (Louisa Jacobson) slept with Larry after a storm stranded them at a hotel. She views it as a terrible mistake, fearing her reputation as an unwed woman with two failed engagements could be ruined if the affair becomes known.
Peggy Scott (Denee Benton) published her book Friends In These Times and accepted Dr. William Kirkland's (Jordan Donica) marriage proposal. His mother, Elizabeth Kirkland (Phylicia Rashad), disapproves of Peggy's writing career and invited her to join the Daughters of Friendship to abandon her professional ambitions.