In Iroquois and Algonquin legend there is the story of a girl who submits in the dark of night to a man she believes to be her brother. Every detail seems to identify him: physical appearance, clothing, a scratched cheek attesting to the heroine's virtue. When formally accused by her, the brother reveals that he has a second self (Sosie) or, more precisely, a double; the bond between them is so strong that everything befalling the one is automatically transmitted to the other : the torn garment, the wounded face. In order to convince his incredulous sister, the young man kills his double before her eyes, but with this single blow he pronounces his own death sentence, since their destinies are one.