Burn After Reading is a bit of a roller coaster in terms of plot. There are tons of random characters that are thrust upon you - and you don't really understand where they all fit in until the movie picks up towards the middle and end.
I guess, technically, the movie revolves around Osbourne Cox (John Malkovich), who quits his job at the CIA after his superiors think he should be demoted. After quitting, Cox decides to start penning his memoirs - which his wife steals as leverage as she begins the divorce process.
Cox's wife, Katie (Tilda Swinton), is cheating on him with another married man, Harry Pfarrer (George Clooney) - and decides to divorce Osbourne and encourages Harry to do the same with his wife so they could be together. Harry meanwhile is also having affairs with a slew of other women.
The action, and most of the laughs, pick up when we are introduced to Linda Litzke (Frances McDormand) - a worker at Hardbodies Gym, an internet dater and someone who is looking for money to pay for four cosmetic surgeries. Pitt's character, Chad Feldheimer, is a co-worker friend of Litzke.
The pair of them find a lost CD, which holds Cox's memoirs (which they believe are government secrets) and Chad believes that if they return it, they should get some sort of reward. Litzke, however, decides to blackmail Cox in order to get the money for her surgeries.
The rest of the movie is pretty chaotic and fun - with some very odd suprises that I was not expecting, but I am not going to ruin it for you.
In the end, everything comes together and all the characters are connected in some way or another
I really enjoyed Pitt's character - and the small role of JK Simmons as a CIA higher up. His lines were very funny and pretty matter-of-factish.
Also pretty funny - the contraption that Harry was building in his basement. I never expected that and it almost floored me.