During an orgy with minor girls, some old and wealthy notables are being murdered by a small group of leftist young revolutionaries. Very soon the police are tracking down Virgile Cabral, the leader of the group. Meanwhile, Virgile's brother and only relative, Vincent, a violonist (and a thief), comes back to Paris. They have not seen each other for three years. Vincent does not believe in the revolution. He only tries to live as he wishes to live. But by looking for his hunted down brother, he has no other choice than to be involved in a fight which is not his.