You'll be in the dark for several minutes as Gyorgy Ligeti's Atmospheres sets the mood. The film is divided into four distinct sections. In the first, prehistoric man is shown as a herbivore, just managing to survive in an inhospitable wilderness. A mysterious black monolith appears, inspiring the use of bones as weapons. Man becomes carnivorous.
Territorial conflicts turn fatal.
Evolution has been given a nudge. In a clever transition to the next section, a bone thrown into the air becomes a satellite orbiting the Earth. We see a space shuttle en route to an orbiting space station, the ensuing docking ballet accompanied by Johann Stauss' Blue Danube Waltz. Here we meet Dr. Heywood Floyd who's traveling to the moon for a briefing on a startling discovery. An extraterrestrial monolith has been found, seemingly buried millions of years earlier.