What is the theme of the Prometheus story?
The primary theme in the story of Prometheus is that rivalry can and does easily lead to chaos. Let's look at this in more detail.
Prometheus is a Titan, one of the group of immortals who warred against Zeus and the other Olympians. Here is the first rivalry that leads to tremendous chaos. Prometheus isn't directly involved in the conflict, however, so Zeus does not exile him, and he actually gives Prometheus the job of creating men.
Prometheus fulfills his task well, and he decides that he would much rather spend time with men than with the gods. In fact, he is not overly fond of Zeus, and he is resentful that Zeus does not want men to have any particular powers. Zeus would rather see Prometheus's beloved creation suffer.
So Prometheus decides that he will steal something very special for men. He throws a golden fruit with a label directed to the most beautiful goddess into the midst of the Olympians. Chaos breaks out at once as the goddesses compete for the fruit while the gods look on. No one notices Prometheus steal the fire.
When Zeus finds out about the theft, though, he punishes both Prometheus and men. Zeus has Prometheus chained to a mountain where an eagle eats his liver over and over again. He has another god make Pandora, the first woman, and he gives her a jar that she is not to open. Pandora, however, is so curious that she opens the jar and unleashes all kinds of horrors and pains on humanity. Rivalry has once again led to chaos.