Zed and Oh are two tribesman. Zed is a hunter and Oh is a gatherer. After being informed Zed ate from Tree of Knowledge of Good and Evil, he is banished from the tribe. Oh decides to go with Zed on his journey to find the end of the Earth. Along the way, they encounter Cain and Abel (David Cross and Paul Rudd), and Abraham (Hank Azaria). After, Zed and Oh notice the girls they wanted to "lay with" (Maya and Eema) from their former tribe have been enslaved, they head off on a journey to save them.

(Source: WikiPedia. Bangs_McCoy)