Sam Mendes won the Best Director Oscar for his debut film, American Beauty. The 1999 black comedy took a jaded view of suburban ennui and emasculated middle-aged men, and while Mendes returns to this subject matter with his adaptation of Richard Yates' cult novel Revolutionary Road, it's hardly a case of an artist reverting to safe, familiar territory. Set in the 1950s, Revolutionary Road stars Leonardo Di Caprio and Kate Winslet -- reunited for the first time since Titanic -- as Frank and April Wheeler, thirtysomething suburbanites who imagine themselves free spirits, but are in fact just as ordinary as all the neighbors they condescend to. He takes the train into the city to work as a white-collar drone for a company that sells "business machines," she's a housewife who once dreamed of becoming an actress. On the surface, they have achieved the middle-class American dream, but in truth, their marriage has deteriorated into an emotionally deadening game of playing house that, after a particularly lacerating argument, sends Frank running into the arms (and bed) of another woman. April, on the other hand, responds to that row by offering a radical change that will shake them out of their rut: she suggests they pack up their two kids and move to Paris. After some discussion, she wins him over with the argument that she will work and he can find what it is he wants to do. They then proceed to gleefully spring the news on their friends and neighbors, who respond with a combination of shock and dismay that tickles the Wheelers' sense of superiority. Soon, however, an unexpected complication throws a wrench in their plan, and forces them to face the truth about themselves. American Beauty laced its darkest moments with sardonic humor, but Revolutionary Road is a pure, undiluted tragedy that offers no reprieve from its microscopic dissection of a doomed relationship. We are treated, in the film's opening minutes, to the moment Frank and April met -- a textbook case of love at first sight. Directly afterward, we see them -- slightly older and very miserable -- seething at each other before erupting into the kind of tumultuous, soul-scarring fight that would usually serve as the end, rather than the beginning, of most domestic dramas. By charting how the couple attempts to rebuild from that fight -- and allowing the audience to watch in horror as they instead fall back into the same unhealthy roles -- Mendes fashions one of the most psychologically penetrating and emotionally affecting portraits of a failed marriage to reach the screen in recent memory. Thankfully, his actors are more than up to the remarkable challenge. Leonardo DiCaprio is ideally cast as Frank, a young man easily stung by his wife's accusations of immaturity. Yet again, as with The Departed, DiCaprio seizes on a role where his baby face underscores a crucial element of the character -- in this case, Frank's inability to understand what it is he really wants in life. That basic confusion about his motivations colors every aspect of his character, and DiCaprio is just as credible when Frank comes close to striking his wife during their horrific fights as he is when he quietly implodes with his own regret. It's a marvelous, detailed performance that grows more impressive with multiple viewings. As his wife, April, Kate Winslet matches DiCaprio's intensity and emotional richness. Unlike Frank, April does know what she wants from life -- and her inability to get it eats away at her until she lashes out at anything and everything around her. Individually they are superb, but in their dramatic showdowns -- particularly in the final take-no-prisoners shouting match, and the eerie fallout from it the next morning -- they create an indelible portrait of how it looks when a couple's love mutates into hate. If nothing else, Revolution Road proves that their Titanic chemistry was no fluke. As if those performances weren't enough, they aren't the only actors who show considerable skill. Michael Shannon, who specializes in playing vaguely threatening oddballs, shines in the tricky role of John Givings, a mentally unstable acquaintance who sees through the facade the Wheelers have constructed for themselves -- he's the only one who congratulates them for their efforts to get out of the suburban rat race. It's a difficult part -- more symbol than three-dimensional character -- but Shannon pulls it off precisely because he brings real emotional truth into a place, the Wheeler home, where lies and self-deception are the norm. And as the Wheeler's neighbors, Kathryn Hahn and David Harbour create their own unique portrait of quiet desperation that, comparatively, gives the Wheeler's fate a certain amount of honor. Indeed, all of the performers in the film truly shine, and all of them can probably thank Sam Mendes for creating an ideal environment. He was the darling of the London theatrical world before jumping into film directing, and this movie -- his fourth -- offers the clearest proof yet that he's integrated his potent stage skills into his career behind the camera. There is a purposefulness to every aspect of the movie: the soundtrack, the lighting, and especially the art direction all work together to create the Wheeler's suffocating outer and inner lives. The film has the inevitable push of great drama, but Mendes always keeps one eye on the character and one on the story -- and by doing so, he makes the Wheelers' relationship both inevitable and believable. That attention to detail makes for a profoundly heavy drama that never once feels heavy-handed.