The Commodore throws his weight around with the Coast Guard to disrupt the delivery of alcohol, which creates an opportunity for Owen to demonstrate his value to Nucky and a struggling casino. Meanwhile, a letter dredges up painful memories for Margaret, Nucky calls in a favor with the U.S. attorney general, Meyer and Lucky learn the price of power, and Lucy searches for ways to cure her loneliness.

Set in early 1918. Ethel's flirting with Major Bryant lands her in trouble as preparations get under way for a concert at Downton. Tensions flare between Isobel and Cora, Edith receives worrying news about Matthew and William, while Branson declares his feelings for Sybil. Robert receives a letter from Carlisle, which causes him concern forcing an uncomfortable conversation with Mary. Mrs Bird's soup kitchen receives a helping hand from Daisy and Mrs Patmore. In the servants’ quarters Mrs Hughes makes a shocking discovery that ends in tears for one member of staff.

Carrie continues to surveil Brody but is unable to follow his actions into his garage which is a blind spot, where Brody begins to perform an Islamic prayer. Meanwhile, Carrie receives visual confirmation from an undercover agent that shows Al-Qaeda member Abu Nazir on video meeting with the Royal Prince of the Kingdom of Saudi Arabia.

Viewers will get a look at Parker and Stone's thought process as they approach a new episode and the 24/7 grind they subject themselves to each time the show is in production. The documentary also includes in-depth interviews with Parker and Stone about their working partnership and reflections on highlights from their careers.

Alicia and Will go toe-to-toe with his ex during a court-ordered mediation. Eli and Diane clash over the best way to handle a dairy company’s PR disaster.