From the introduction:
The campaign always lasts seven nights and seven days. The game master needs to keep a count of the number of night and day phases played to determine if a raid occurs during a phase and to end the campaign.
The game ends on the seventh day. After determining where the bombs exploded on the seventh night, NPCs should tell the characters that a portion of the inhabitants have decided to try to evacuate the city and cross the desert. Ask each player why his or her character joins the voyage or remains to continue the defense of the city. If all characters do not make the same decision, the game ends with a farewell scene. Otherwise, end the game on a scene featuring the exodus from the city or the result of the continued resistance.