They are accused of 'plotting' the assassination of the prime minister. = They are accused of 'plotting' to assassinate the prime minister.
As the 'plot' unfolds [=as the story continues; as things happen in the novel, movie, etc.], we learn more about the hero's family.
He is a master of 'plot' [=he is very good at thinking of interesting stories], but his characters are not realistic.
(..) Did you guys see that? I was all like... Do you actually believe this is the warrior destined to defeat me? I do not. I know he is. Oh, look at him. A lifetime to plot his revenge - and he comes to me on his knees. - What? A lifetime? I did not have a lifetime. We only heard about Master Rhino (..)2011 Kung Fu Panda 2
(..) They're in Gongmen Jail on Black Dragon Alley. What? They're still alive? They must be in that jail gathering intelligence, hatching a plot to use their awesomeness to defeat the weapon! OK, let's go! - Thanks, sheep. - Hey! Stop that costume! - Hold it right there! (..)2011 Kung Fu Panda 2