The final episode explores how the September 11th attack came to be. A portrait emerges of the true mastermind of the attack, Khalid Sheikh Mohammed. Part three explores his past, including time spent in the US as a college student, through interviews with friends, journalists and the agents who devoted their lives to finding him. The episode also looks at the men recruited to enact the attacks–their backgrounds, terror training, their lives in the US and their flight training. In Washington, there is a disconnect between government agencies–information withheld, missed signals, and ensuing tensions. The film also details the experience and emotion of 9/11, and how the United States and the world were changed forever.