Algiers. June 1955. Khadidja has left Kabylie to join her older brother Malek in Algiers. On this, her first day in the city, and while waiting to be able to enroll in school, she accompanies him to the market where he has a small fruit and vegetable stall. But the day does not go as planned: following an altercation with the police, Malek is arrested. Khadidja finds herself alone. Fortunately, Lyes, a resourceful and clever street child, takes her in at his makeshift shelter cobbled together on the rooftops of the Casbah. It is there that she meets Philippe and Ahmed, two children from Bab-el-Oued who come here after school. The three boys will help her settle in and, most importantly, to decipher a coded message passed on by Malek. Together, they investigate across the city and pick up the trail of the mysterious "Oranaise" who might just be able to help them free Khadidja's older brother.