25 years ago, when Princess Diana of Wales spoke out on national television, she shocked the entire country. She revealed a precarious royal marriage, infidelity between both parties, and a certain degree of personal pain that caused her to fall seriously ill. This is a watershed television program that has influenced the public's perception of monarchy and triggered a constitutional crisis. But what led to this extraordinary moment? In this two-part series, the British independent television station listened to the opinions of those who witnessed marriages falling into tragedy, and discovered how and why this unusual interview occurred through previously unseen documents and videos, as well as eyewitness testimony in the room.