Based on the novel by John le Carré, Tinker Tailor Soldier Spy follows Cold War-era secret agent George Smiley (Gary Oldman) as he attempts to ferret out a mole contained within the upper echelons of British Intelligence. Director Tomas Alfredson, working from Bridget O'Connor and Peter Straughan's screenplay, has infused Tinker Tailor Soldier Spy with an almost excessively deliberate pace that isn't, at the outset, as disastrous as one might have feared, as the film's evocative and palpably atmospheric visuals prove instrumental in initially capturing the viewer's interest - with the perfectly watchable vibe heightened by a selection of uniformly stirring performances. (In addition to Oldman's expectedly first-class turn, the movie boasts strong work from folks like Colin Firth, Tom Hardy, and John Hurt.) There's little doubt, however, that the film's pervasive lack of context becomes more and more problematic as time goes on, with the frequently baffling narrative compounded by a curious absence of high-energy interludes and, ultimately, triggering Tinker Tailor Soldier Spy's transformation from a promising political thriller into an often interminable period drama. The film's progressively uninvolving atmosphere prevents the viewer from working up any real interest in Smiley's endeavors on an increasingly demonstrable basis, which inevitably ensures that the movie's final half hour is simply unable to pack the visceral gut-punch that Alfredson has clearly intended. The end result is a meticulously conceived and executed adaptation that is, unfortunately, dramatically inert virtually from start to finish, and it does seem entirely likely that one's appreciation for the film is directly related to one's familiarity with the original source material.