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.
(..) counteracted the biotoxins. Residents of Lower Manhattan can rest peacefully... ...knowing that the alleged mastermind... ...of this terror plot, Dr. Curtis Connors, is behind bars. ...on the street for a report in Lower Manhattan. Sweetheart, it's all right. It's all right. (..)2012 The Amazing Spider-Man