The first half, Titanic: Death of a Dream, encapsulates the first two hours. It tells the story of the RMS Titanic's origins, from its conception and construction, to its maiden voyage, leading up to the initial collision with the iceberg that would ultimately sink the ship.
The second half, Titanic: The Legend Lives On, concentrates on the ship's sinking, its immediate aftermath, and its discovery in 1985 by Dr. Robert Ballard, along with Titanic's continuing legacy.