Belief
Early on in the film we see David invading Shaw's memories about her belief system formed with her father as a little girl. He tells her that he believes her mother is in a better place because that's what he chooses to believe, not because it's what he knows for sure. This belief system has led Shaw to seek out the planets where she believes she is called in order to find out where we came from and affirm her beliefs about God, creation and death.
Betrayal
Throughout the film we see betrayal after betrayal at the hands of David a being of artificial intelligence created by Peter Weyland. Weyland has enlisted David to find the key to immortality. The first betrayal is that Weyland lies and tells everyone he is dead when in actuality he is dying but alive. In order to find this key to immortality Weyland orders David to infect Holloway with the alien DNA, thus killing the man after he impregnates his love, Shaw. David also betrays Vickers by not letting her in on all of the secrets Weyland shares with him in private, meaning that she doesn't actually know what the true mission is. Thus, no one on the Prometheus actually knows why they are there, and because they are serving their own interests at beginning David is able to use them as pawns in Weyland's elaborate plan for survival. In the end, Weyland believes what he is doing is so right that he goes before the advanced being expecting to be given the key to life. Instead, his hope is betrayed and he is killed.
Origins of Life and Death
Prometheus is a film that plays off the mythology of the character by the same name who stole fire from the gods and gave it to man. Thus the theme of creation is throughout the film. Who created us, where have we come from, where are we going? All of these questions are plum lines guiding characters in the film. Weyland wishes to metaphorically steal fire from these advanced beings in order to live longer. He seeks to be immortal thus is willing to play a dangerous game and risk others' lives to find it. Shaw goes to the distant planet in order to prove her beliefs about how we were created and where we go when we die are true. She believes the answers lie in this invitation to a far away planet. Yet, like Prometheus in the myth, the ship's crew is cast away from the presence of the advanced beings as they got to close to the sun, metaphorically speaking.
