Romeo goes to clean Professor Casella's fireplace who, to thank him, gives him an illustrated book. However, Romeo cannot read, so the teacher offers to teach him to write his name. Upon his return home, he finds a letter left by the girl who lives in the same house, Angeletta. But, how will Romeo know interpret what is written on it?

After a long time, Romeo and Alfredo finally reunited and joined other young chimney sweeps to form the Black Brothers fraternity with Alfredo in command to confront the Wolf Pack. Romeo tries harder to learn to read inspired by Alfredo. Knowing that Alfredo only has one book and that it is in poor condition, Romeo introduces him to Professor Casella, who offers him to choose a book. Alfredo borrows one from Voltaire dealing with freedom and equality.

Romeo and Angeletta meet the old puppeteer Teo and little Nana. Teo has a sad secret: Leon, his son, left him and his granddaughter after a quarrel. He would rather be a doctor than a puppeteer. Now Teo wishes nothing more than to see his son again. Angeletta asks Romeo and the Black Brothers to find Leon. Also, Matteo is about to reveal a secret about Angeletta to Romeo while talking with Rossi.

Angeletta's condition is deteriorating rapidly. The so-called Ice Queen Montovani wants nothing to do with her granddaughter. Even asking chimney sweep Rossi is useless. The Black Brothers therefore clog the chimneys of Montovani Castle. They want to force the Countess to stay in touch with Angeletta.

In Milan, a wedding of the nobility is taking place and all rich and noble people of the area are invited. Even the king of Italy is expected to come. Then Romeo accidentally meets Bianca, Alfredo's sister who was believed to be missing. When he conveys the good news to him, he learns Alfredo's mysterious story.

Professor Casella discovers that Alfredo's illness is worse than initially thought. Alfredo also knows that he will not live much longer. Nevertheless, he firmly intends of showing up before the King of Italy with his sister Bianca to expose his aunt and uncle by showing the king the authentic royal insignia. To achieve this, he thinks up a plan with the help of the Black Brothers to sneak into the duke's wedding banquet.

Romeo suffers greatly from the sudden death of his friend Alfredo. He sinks into a deep sadness and distances himself more and more from reality. The Black Brothers try to cheer Romeo up again. But even when Dante tries to force him come to his senses, Romeo remains withdrawn.

While working one day, Romeo falls from a chimney and breaks his leg. Professor Casella agrees to have him at his place until his leg heals. So that means that Romeo and Bianca will spend Christmas together. Romeo challenges to read Alfredo's favorite book, Moby-Dick, while his leg heals. The professor interests them both in many subjects, and Bianca begins to see Professor Casella as a father. They want to thank Professor Casella for his kindness, so they prepare a special show in Christmass Eve.

Spring has fallen and Romeo's contract with Maestro Rossi is over. It is time for Romeo to say goodbye to Milan and return home in Sonogno. Some of his friends have already left, while others still have to stay a while longer. Professor Casella offers to drive Romeo and the other boys halfway to their home towns along with Bianca. Before leaving, they visit Alfredo's grave one last time, where they meet the Wolf Pack.