Enid Baines is a movie censor for the Thatcher government. While reviewing horror movies, she thinks she recognizes her missing sister, and Enid herself begins to recall lost memories. Roughly at this point, Censor swerves into the surrealistic and abandons the plot. Either that, or Enid becomes psychotic and the rest of the movie is her hallucinations.
Maybe the movie was trying to make a point about censorship or Thatcher or mental illness or horror films, or maybe it's just some surrealistic delirium, but whatever it was, it wasn't my cup of tea.