The plot focuses on an expedition funded by the Weyland Corporation, deep into outer space following the discovery of a galactic map of sorts, possibly explaining the origins of humanity and the universe itself.
This epic 3-minute trailer showcases a new alien life form (the bad guys basically), breathtaking worlds, the Space Jockey beings and yes, minor details of the upcoming movie. The cast includes: Charlize Theron is Vickers, a Weyland employee traveling along to monitor the expedition; Michael Fassbender as David, an eighth-generation android developed by Weyland Corp and Noomi Rapace as an archaeologist who discovers the so-called star map found within separate cultural ruins and is also a key protagonist of the film.
Here are a few movie related links:
Weyland Industries - 20th Century Fox website showcasing the background story
Project Prometheus - Technologies developed by Weyland Corporation
Prometheus Movie - Fantastic fan website with a tremendous collection of media and information
Image and trailer copyright 20th Century Fox