In Prelude 2, you are thrown right into the action, not only on Mars, but on Venus and the colonies and as well, and the political arena is set for turmoil as you jumpstart your game. With actions and effects on your Preludes, Mars will never be the same again!
In Prelude 2 most of the cards are specifically connected to other expansions of Terraforming Mars (Venus, Colonies, Turmoil). The 5 corporations and 13 of hte Prelude cards are playbel without any of these expansions.
