Una mujer. Un hombre. Una ciudad. Dos personas con problemas cuyos destinos acaso se crucen. Mathilde y Thibault. Dos siluetas que se desplazan por París entre millones de personas. Ella perdió a su marido, se ha quedado a cargo de los tres hijos y encuentra un motivo para levantarse cada día, su salvación, en su trabajo en el departamento de marketing de una empresa alimentaria. Él es médico y recorre la ciudad entre un tráfico infernal visitando a pacientes, que en ocasiones tan solo buscan que alguien los escuche. Ella empieza a sufrir acoso en el trabajo por parte de su jefe. Él se enfrenta a la decisión de romper con su pareja. Ambos están en crisis y sus vidas van a dar un vuelco. ¿Están estos dos desconocidos destinados a cruzarse y conocerse?
Every day Mathilde takes the Metro, then the commuter train, to the office of a large multi-national where she works in the marketing department. Every day, the same routine, the same trains. But something happened a while ago - she dared to voice a different opinion from her moody boss, Jacques. Bit by bit she finds herself frozen out of everything, with no work to do. Thibault is a paramedic. Every day he drives to the addresses he receives from his controller. The city spares him no grief: traffic jams, elusive parking spaces, delivery trucks blocking his route. He is well aware that he may be the only human being many of the people he visits will see for the entire day and is well acquainted with the symptomatic illnesses, the major disasters, the hustle and bustle, and, of course, the immense, pervading loneliness of the city. Before one day in May, Mathilde and Thibault had never met. They were just two anonymous figures in a crowd, pushed and shoved and pressured continuously by the loveless, urban world.