We meet our protagonist, Snowman, in the aftermath of an apocolyptic disaster, apparently the only human survivor 
 moves back and forth pre and post 'apocalypse' 
 pre world of corporations manipulating genetics and creating hybrid animals 
 Snowman best friend, Crake, is wunderkind in a genetic brewery, but already somewhat disengaged from humanity - in particular those outside the corporate elite zones - and seems to be pushed over the edge on discovering the level of disregard and profit seeking these corps engage in 
 (view spoiler)[Ultimately he creates an idealised version of humans with none of the flaws he sees in the original (take away religious leaning, artistic mindset, sexual motivation etc.) and these have survived the apocalypse - a virus Crake created. (hide spoiler)] 
 post world is filled with Snowman's lonely regrets and his attempts to build a mythology for the surviving Crake's children