Number Two believes that Number Six resigned because he was going to sell out. Using dream manipulation, Number Two tries to determine which one of three possible candidates Number Six was dealing with.
Number Six wakes up with a new identity. Now he's Number Twelve. Worse, Number Two asks him to impersonate someone--Number Six. But the new Number Six is more like him than he is.
With his mind transferred to another body, Number Six wakes up in his London flat and can't convince his colleagues who he is. He takes off to Austria to find the one man who can help him, the person whom Number Two wants him to find.
In a Wild West setting, a lawman who resigned is trapped in a town called Harmony where the Judge wants him to be the new sheriff - by hook or by crook.
After witnessing the trials of Number Two and Number Forty-Eight and meeting the President of the Assembly, Number Six escapes during the chaos that follows.