In Season Four of The Diplomat, two marriages threaten to eat each other alive. One catastrophic moment shatters the fragile peace Kate Wyler brokered between the US and UK, as well as the crumbling marriage she's trying to save. While she fights to stem the bleeding, President Grace Penn and VP Hal Wyler's conspiracy to steal Russia's most powerful weapon hurtles the United States toward war. Kate and Todd, at best an uneasy pair, unite to stop the Grace-Hal alliance from upending the balance of power abroad and at home. Four Emmy nominees paint an unmissable portrait of two marriages: Keri Russell as Ambassador Kate Wyler, Rufus Sewell as Vice President Hal Wyler, Allison Janney as President Grace Penn, and Bradley Whitford as Todd Penn.