Compared to its previous three seasons of gripping—but often slow-moving—royal drama, The Crown season 4 is truly action-packed. Within the first hour of the new season, Prince Charles meets his future bride Diana Spencer, Margaret Thatcher is elected Britain's first female prime minister, and a major character is killed in an explosion. The loss of Lord Louis Mountbatten (Charles Dance)—Prince Philip's uncle and father figure to Prince Charles, known as "Uncle Dickie" in the series—is a shock that has a ripple effect throughout the season. Here's the true story of his assassination.