Paris today, a working-class neighbourhood, a square. Two bars stand facing each other as they would in the main street of a town in the Far West. Marie is 25 years old and has come back to Paris after a long absence in search of her brother, Antoine. She finds a young man who has changed. He hangs out with a rough crowd and is killed soon afterwards in circumstances that are unclear. Marie will move heaven and earth to avenge her brother's death.