In early 1970s London, middle-aged former spy George Smiley (Gary Oldman) finds indications that one of his former colleagues in the leadership of British Intelligence might be a Russian mole. Smiley gathers a small team of allies, including his right-hand man Peter Guillam ("Sherlock's" Benedict Cumberbatch), to unravel the truth.
Tinker Tailor boasts the most colorful cast of British actors this side of Hogwarts, including Toby Jones and Colin Firth as high-ranking potential traitors, Tom Hardy as a pugnacious, untrustworthy source, and John Hurt, in flashbacks, as the Circus's ill-fated former director. Director Tomas Alfredson (Let the Right One In) portrays "The Circus" (Smiley's nickname for British Intelligence, based in Piccadilly Circus) as a hidebound organization rife with paranoia and corruption. It's hard to tell whether the Circus or Margin Call's collapsing investment bank is 2011's most compromised institution.
It's fortunate that Tinker Tailor works so well as a mood piece, because the plot can be dizzyingly dense. Audiences may need to watch it once for its atmosphere and a second time to appreciate how all the pieces fit together, which is a lot to demand of a viewer. Oldman, in a similar, soft-spoken mode as his Commissioner Gordon performances, conveys Smiley as a dogged investigator despite his emotional desolation, a Cold Warrior as scarred on the inside as real veterans may be on the outside.