Season 4 brings Kate Wyler face-to-face with a crisis that hits much closer to home. After a catastrophic event threatens the fragile peace she brokered between the US and UK, Kate discovers that President Grace Penn and Vice President Hal Wyler are involved in a conspiracy to steal Russia’s most powerful weapon. With the move threatening to push the United States toward war, Kate teams up with the unlikely Todd Penn to stop Grace and Hal before their alliance throws the global balance of power into chaos.