Part Four of the series "Time: The Story of Existence." Examines time's behavior on a wide range of scales from atomic nuclei to black holes. Demonstrates that time travel is theoretically possible by entertaining several questions: What fate awaits stars and galaxies? If the stars eventually die, what will happen in the dark ages that follow? Are the beginning and the end of the universe linked to the birth and death of time? Hosted by Michio Kaku. Original BBC series title: "Cosmic Time." Accessibility options on the DVD are: (1) audio description, (2) expanded description, (3) subtitles for the deaf and hard of hearing.