In her still-short career, Anne Hathaway has never been anything less than fine. Whether playing an unkempt teenage girl who learns she is to become royalty in 2001's "The Princess Diaries," a rodeo gal who marries someone who cannot love her back in 2005's "Brokeback Mountain," a graduate student who gets way in over her head after being hired at a trendy Manhattan fashion magazine in 2006's "The Devil Wears Prada," or a middle-aged spy with a new, much younger face in 2008's "Get Smart," Hathaway sells her roles and makes even the daffier ones believable. Nothing on her résumé, however, could prepare audiences for what Hathaway has achieved with "Rachel Getting Married," a searing family drama that emotionally cuts to the bone. This is a revelatory performance—bold but not flashy, achingly real but never saccharine, breathtaking in its fearless modulations while remaining steadfastly naturalistic.

Moving down the line, when was the last time director Jonathan Demme (2002's "The Truth About Charlie") has been this loose yet assured in his filmmaking craft? Has he ever? "Rachel Getting Married" is an indie feature rather than a razzle-dazzle Hollywood production—this is clear from the start with its grainy, predominantly handheld camerawork by Declan Quinn (2004's "Vanity Fair") and abandonment of most dumbed-down writing conventions in Jenny Lumet's sterling screenplay—but it is so honest in the tough places it goes and so humane in its portrait of an ailing American family that teenage and adult viewers should be able to unconditionally latch onto and identify with it.

Rachel (Rosemarie DeWitt) is, indeed, getting married, and troubled younger sister Kym (Anne Hathaway) is being let out of the rehabilitation facility she has been residing at for the last several months in order to attend the weekend preparations and festivities. Kym, a former drug addict hoping to finally stay clean, is well aware that all eyes are on her, from father Paul's (Bill Irwin) babying approach, offering her food at every turn and denying her the use of his car, or Rachel's initial decision to induct friend Emma (Anisa George) as maid of honor instead of her own sibling. It is made clear through her actions that Kym is a narcissist, always yearning to have the last word, and Rachel is all too aware of this. Still, something darker simmers and boils beneath the surface of this family, extending out to also include Kym's and Rachel's distant mother Abby (Debra Winger), and it is only a matter of time before the unhealed wounds of the past explode upon the present.

With the exception of perhaps too much time focusing on the music being played at the wedding reception near the end, "Rachel Getting Married" scarcely takes a wrong step. This is a remarkably sharp and authentic slice-of-life, so suggestive and intuitive of the way family members interact in a variety of situations that the viewer starts to believe what he or she is watching is a documentary. With the camera following Kym around as she observes the amount of strangers and wedding hysteria going on inside her childhood home—there is even a hired band who linger in the background and play their instruments to the increased annoyance of the characters—we in many ways become her, seeing through her eyes. And yet, in scenes such as a particularly uncomfortable one where everyone is making rehearsal dinner speeches to bride Rachel and groom Sidney (Tunde Adebimpe), we recoil with the characters, deathly afraid of what loose cannon Kym might utter when it's her turn to talk.

The ins and outs of a wedding are keenly portrayed by director Jonathan Demme, used as flavorful backdrop to the human story going on in the forefront. When revelations are finally uncovered and the viewer is given the full picture of what has happened in this family's life to damage them so badly, the results are devastating, performed to perfection from Rosemarie DeWitt (2005's "Cinderella Man"), as wearied sister Rachel; Bill Irwin (2007's "Across the Universe"), heartbreakingly trying in vain to keep peace with everyone while unraveling himself as father Paul; and a very welcome, rarely seen anymore Debra Winger, a cage of silent grief and resentment as mother Abby. If an actor could actually pull out their soul and show it off for the world to see, one imagines it would be Anne Hathaway to achieve this feat. As marvelously in-tune as everyone else is, Hathaway is the fiery light at the center of "Rachel Getting Married." Painfully flawed and sometimes frustrating, Kym is nonetheless intimately viewed as someone to empathize with, her broken life a cause and effect of the demons in her closet. Hathaway's performance is one that Oscar voters would be remiss to overlook come next year.

Wrenching and uncompromising, but not without an all-important glimmer of hope in its façade, "Rachel Getting Married" is sure to tie the viewers' feelings up in knots (and wring a number of well-earned tears, as well). Caring deeply about the lead characters and the impending nuptials, the film travels down some lonely, stark roads in its journey to the other side. Director Jonathan Demme wisely does not wrap all of the relationships up in a neat package by the conclusion—there is still a long way to go for the healing to finish—but offers up subtle, astoundingly effective suggestions of where things stand. Kym's desire to reach out to her parents, now separated, is beautifully encapsulated in a moment where she spies her father through a window and quietly says to herself, "Dad." Her bond, dysfunctional though it may be, with older sis Rachel is more soundly concluded, in a simple exchange of words and body expressions that say it all. And as for sad-eyed, black sheep Kym, will she be okay? The picture does not tell, because her future has not yet been written. All we can do is cross our fingers, and wish her the best.