“Blue Valentine,” a new film starring Ryan Gosling and Michelle Williams, depicts a relationship gone sour.

Although the film got an NC-17 rating reportedly for nudity, perhaps it should have instead earned this rating for being too depressing for anyone under 17.

Director Derek Cianfrance’s new movie shows the evolution of a marriage that seems promising at the start but ultimately ends in divorce.

The film begins with the downfall of the marriage, when Dean (Gosling) and Cindy (Williams) discover that their dog has gone missing. When Cindy learns of the dog’s death, it seems to be a breaking point. In an attempt to salvage their marriage, Dean suggests that the couple escape for the night to a sleazy motel two hours away, near where the couple first met.

With intermittent flashbacks of the couple’s early relationship, the film shows with heartbreaking clarity how perfect the two seemed for each other in the beginning. The flashbacks help the film maintain a steady pace, with two stories being told simultaneously: the beginning and ending of a romance. The direction of the film is also poetic, especially in the way we enter the story with the death of the dog and leave the story with the death of the relationship.

The structure of the film provides depth and helps the audience understand who these characters are, what they have experienced and why they behave the way they do. Weaving scenes from when the couple first met and fell in love with scenes from the night at the hotel when their marriage dissolved, the film makes even romantic moments of innocent love seem bittersweet.

“Blue Valentine” is an effective character study, like “Revolutionary Road” for a younger generation. What is simultaneously most unsettling and most outstanding about the film is that the dialogue never seems forced or over-the-top. Gosling and Williams’s performances are flawless; the two actors carry the movie and are one reason why the film is as great as it is.

“Blue Valentine” will be in theaters Dec. 31.