Others have provided detailed synopses of the story. I would rather you just take it as it comes and enjoy how different the plot development is. As a matter of fact, watch this film and try to appreciate how different it is from the ordinary American fare no simple boy meets girl romance here. These beautiful people aren't young, chic urbanites wearing designer clothes they can't afford, living in apartments featured in Architectural Digest. We have three young women (Ludivine Sagnier, Clotilde Hesme, and Chiara Mastroianni) who lack the assistance of a personal shopper or a Beverly Hills stylist, but do not lack beauty or sensuality. Also, as a 59 year old man, I have to mention Brigitte Roüan, who shows how attractive a French grandmother can be. The men are similarly attractive. Louis Garrel demonstrates why he is currently the hottest actor in France. Newcomer Grégoire Leprince-Ringuet is disarmingly charming.
But this is a musical. You will find no potential American Idols here. The actors are not going to dazzle you with vocal gymnastics. The numbers have no clever arrangements or over produced orchestration. You have evocative lyrics set to a score reminiscent of US folk music in the 1960s or more exactly, French coffee houses. One word of caution, the English subtitles are quite misleading at times. My college French is a little rusty, but a review of the French subtitles gave me an appreciation of how descriptive the lyrics are.
Finally, there is no gratuitous violence or nudity, but look for the number Ma Memoire Sale (My Soiled Memory), where Ismael begs to be cleansed of the painful memory of his lost love. Some may be shocked at the scene, but you can't deny the passion and pain that permeates the number.
I have downloaded the soundtrack and ordered the DVD for this is like a good French dish, an experience to linger over.