Khadidja has just arrived in Algiers, at her brother Malek’s place, who is soon to enroll her in school. With him, she discovers Algiers, the White City, and the reality of life there in 1955.

Khadidja wakes up after her first night in Lyes’s shack. The two children decide to go to Malek's place to collect Khadidja's belongings and some food before the modest apartment is rented out to a new family. They are caught by two men who come to search the room, clearly looking for something. After they leave, the young girl realizes that she will have to stay in the shack for an indefinite period. Lyes then asks a big favor from Philippe to improve his guest's daily life: to give her his mattress. In exchange, he promises to introduce him to his idol, the boxer Alphonse Halimi, who is fighting in a match in Algiers that same evening.

Khadidja now has a mattress, but the shack is still very rundown, especially when it rains. The whole gang sets off for the Ravine of the Wild Woman, a wooded area known for being haunted, to find materials to build a roof.

Mr. Germain, Philippe and Ahmed’s teacher who also works as a letter writer at the Barberousse prison, hands the boys a letter that Malek wrote to Khadidja. However, Philippe, still angry with Lyes over the tomato-throwing incident, refuses to go back to the shack. Ahmed, Lyes, and Khadidja read Malek’s letter; they believe it hints that they should find Reinette L’Oranaise, the famous singer. Could she help them free the young man? They set out to look for her, unaware that young Guy, determined to avenge his father, is secretly following them in the shadows. Will Philippe return to help his friends?

It’s an important day for Philippe’s father: his boss has invited the whole family for lunch at the beach. Philippe is thrilled but a bit nervous because he will see Annie, whom he secretly loves. He tries to get her attention but is interrupted by the unexpected arrival of Guy, who, unwittingly, boosts Philippe’s image in Annie’s eyes. Furious, Guy leaves and threatens to destroy the shack. Philippe needs to warn Ahmed quickly, but he can’t do it right away. Stuck at lunch with Annie, Philippe doesn’t know how to get away from the meal. Fortunately, Annie comes to his rescue.

The children devise a plan to retrieve the notebook from Guy: Lyes has to get it without being noticed. Time is running out, and Khadidja’s meeting with Nejib is approaching fast. But the plan goes awry when Guy’s father arrives unexpectedly and recognizes Lyes. The young messenger returns empty-handed, much to Khadidja’s despair. Philippe then decides to take matters into his own hands and proposes to win back the notebook fair and square in a boxing match with Guy.