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.
(..) I didn't understand the script. Iunderstood enough to say I liked it ... ... but every time I read it and we got closer, I understood more. I had questions forever and would've constantly tried to change the plot ... ... and they were, "Now Bill, Bill, Bill ... ... ou just don't understand." (..)2001 The Matrix Revisited