Everything you need to understand or teach The Empire of a Thousand Planets (Valerian) by Pierre Christin.
Valerian and Laureline are on a mission to Syrte. Earth has sent probes ahead to gather information about the planet, so Valerian and Laureline have some basic information upon their arrival. A group called the Enlighteneds are in control, but Valerian soon discovers they are the immortal remnants of a failed mission from Earth, intent on revenge against the planet that sent them out. The novel's themes are the need for goals, freedom, and the roles of the hero and his sidekick.