蓝，是关于音乐的一部

Julie (Juliette Binoche), the wife of the famous French composer Patrice de Courcy, loses her husband and daughter in an automobile accident she herself survives. While recovering in a hospital, Julie attempts suicide by overdosing on pills, but cannot swallow them. After being released from the hospital, Julie, who it is suggested wrote (or helped to write) much of her husband's famous pieces, destroys what is left of them. Calling Olivier (Benoît Régent), a collaborator of her husband's who has always admired her, she sleeps with him before bidding him goodbye. Emptying the family house and putting it up for sale, she takes an apartment in Paris near Rue Mouffetard without telling anyone, her only memento being a mobile of blue beads that is hinted to have belonged to her daughter.

Julie disassociates herself from her past life and distances herself from former friendships, even being no longer recognized by her mother, who suffers from Alzheimer's. She also reclaims and destroys the unfinished score for her late husband's last commissioned work − a piece celebrating European unity following the end of the Cold War. Excerpts of its music, however, haunt her throughout the film.

Despite her desire to live anonymously and alone, Julie is soon confronted by her past. A boy who witnessed the accident meets Julie and gives her a cross necklace found at the scene and asks her about her husband's last words, the punchline of an indelicate joke; Julie allows the boy to keep the necklace. Julie also reluctantly befriends an exotic dancer named Lucille (Charlotte Véry) who is having an affair with one of her neighbors and is despised by most people in the apartment building. The two women would support each other emotionally. While comforting Lucille at the club where she works, Julie sees Olivier being interviewed on TV, revealing that he kept a copy of the European piece and plans to finish it himself; Julie then sees a picture of Patrice with another woman.

Julie confronts Olivier about the European piece and asks him about the woman seen with Patrice. She tracks down Sandrine (Florence Pernel), a lawyer and Patrice's lover, and finds out that she is pregnant with his child; Julie arranges for her to have the family house, not yet sold, and eventual recognition of his paternity for the child. Julie then returns to working on the piece with Olivier and finishes the final part. She then calls Olivier, who refuses to take the piece as his own unless Julie is credited as well, to which Julie agrees. Julie then calls Olivier again, asks him if he still loves her; he says yes, and Julie proceeds to meet him.

In the final sequence, part of the completed Unity of Europe piece is played (which features chorus and a solo soprano singing in Greek the praise of divine love in Saint Paul's first letter to the Corinthians) and images are seen of all the people Julie has affected by her actions. The film ends with a shot of Julie crying before she begins to smile gradually.