The film focuses on a 1973 investigation of the British intelligence service by one of its former members in an attempt to find a mole. Gary Oldman plays this former agent, George Smiley. Oldman's precise diction and eloquent pauses define the character as an extremely careful man who misses nothing. The supporting cast is excellent as well; each intelligence member has their own quirks and their own story.
Opening with a botched intelligence operation, the film quickly moves through a change of leadership at the British intelligence service (called The Circus by its members) and the ousting of George and his direct supervisor Control (the man who ordered the botched operation). After this, George’s investigation begins and the plot thickens as he must clear each of the remaining leaders of the intelligence service to stop the mole from revealing British secrets to the Russians. The film also contains many flashback scenes which allow the viewer to follow George’s train of thought as he conducts his investigation.
I would recommend this film to anyone who is at all interested in the spy movie genre, as well as anyone who likes films which make them think. The ending of the film is both fascinating and morally complex, and anyone who likes those things in combination should do themselves a favor, and see this film.