In the Tavares Bastos favela, Rio de Janeiro, Martinho Toscano desperately runs away from someone who wants to get their hands on his investigation. He ends up dead, but frustrates the killer's expectations by having only blank papers in his possession. The research, which he kept secret even from the people who hired him, remains secure. Toscano's death deeply disturbs Tomás Noronha, his disciple, who in the meantime is dealing with a failed marriage with Constança and the heart disease of his daughter Margarida, who has Trisomy 21. The possibility of continuing the mentor's work becomes a reality when he is contacted by Nelson Moliarti, from the Américo Vespúcio Foundation. They want Toscano's investigation and pay him a fortune to get it done. Tomás accepts, but when he is attacked by a stranger before traveling to Brazil, he begins to think that he may have made an error in judgment.
Tomás learns that Martinho Toscano may have been murdered. Now he is the cryptanalyst who fears for his life and thinks about giving up on the agreement he made with Nelson Moliarti and John Savigliano, president of the Américo Vespúcio Foundation. Meanwhile, Constança helps Toscano's widow, who was diagnosed with Alzheimer's, to return home, after she unsuccessfully tried to contact Tomás before he traveled to Brazil. At the college, a plenary of students calling for the end of colonialist symbols generates concern among teachers. We learn that Tomás's colleague, Vitória, leads a group of students who clandestinely attack the symbols of the Discoveries and slavery figures.
The siege tightens around Tomás. He tries to talk to Toscano's widow, who suffers from Alzheimer's and doesn't remember looking for him. Only later, in a moment of lucidity, does Luísa take him to Toscano's tomb, where she shows him a safe that her husband left her and a riddle for Tomás to solve. The cryptanalyst strives to decipher the enigma as he becomes increasingly involved with Helena. Vitória is seriously injured in a confrontation with neo-Nazis, in an attempt to vandalize the Padrão dos Descobrimentos. Pressured by the foundation for answers, Tomás travels to Genoa and relates the enigma that was left to open the safe with Umberto Eco's work, "Foucault's Pendulum". The discovery is interrupted by the arrival of a mysterious woman, Manuella, who wants to talk to him about the Foundation but, upon realizing that they are being watched, she invites him to follow her. On the street, the two are chased and Manuella is fatally run over before she can tell what she knows.
Tomás discovers Manuella's connections to Savigliano. Upon returning to Lisbon, he feels increasingly watched and suspicious of the Foundation, still without imagining that Diogo is watching him through video surveillance cameras and that Helena is working for the institution. Moliarti is unhappy with the direction of the investigation, which indicates flaws regarding the theory that Columbus was Genoese, but Tomás remains determined to see it through to the end. Meanwhile, during a new attack on the statue of Father António Vieira, Bruno and Afonso are saved by Tomás, who helps them escape from the police, putting his life in danger. Margarida undergoes urgent heart surgery, leaving Tomás and Constança shocked. The surgery turns out to be successful.
Tomás opens the safe, but is unable to decipher all the information that Toscano kept. One of the clues leads him to Count Vilarigues, an acquaintance from Toscano, who makes reference to a document present in the national library - CODEX 632 - which proves the truth about the origin of Columbus. After discovering the cameras in his apartment, and Constança telling him that she caught Helena at his house, Tomás realizes that he is entangled in a web of lies that is bigger and more dangerous than he could have ever imagined. Constança also tells him about her relationship with Diogo and her suspicions about him. We now realize the Spaniard's true intention: to prove that he is Columbus's heir. Unable to make an agreement with Diogo, the Foundation decides to kill him, but creates a scenario so that everyone believes he escaped and that he was the one who ordered Toscano's death.
Tomás decides to reveal the truth to the world about Columbus's origins. He returns to the National Library, but when requesting CODEX 632, he realizes that the page has been torn out. Tomás knows that the proof could be lost forever, but upon learning of Savigliano's collecting spirit he decides to plan an assault on the foundation with the help of Rodrigo and Vitória. Despite some surprises, the robbery goes as planned, but, just as Tomás prepares to show the evidence to the Portuguese Government, he realizes that the Foundation has kidnapped his daughter. The final confrontation with Savigliano and Moliarti turns into a police chase, as Inspector Froes intervenes with a PJ team.
