Communicating visually, not verbally, 3 and 4 are the scholarly twins who voraciously catalogue everything they can see and find, recording and building a massive database for the group of the world that surrounds them and the history that led up to their creation. 

9 takes place in a world parallel to our own, in which our very humanity is threatened. A group of rag dolls living a post-apocalyptic existence discover one of their own, 9, who may be the key to their survival.