Lorenza invites the editors to attend the exhibit opening for an acquaintance named Riccardo. Riccardo’s work references Christian iconography, though the largest work is entitled Sophia. At the opening, Belbo asks Lorenza about her relationship with Agliè and learns that they call each other “Simon” and “Sophia” in reference to an origin story where God created woman before man and named her “Sophia.” While creating the world, Sophia was trapped and became prisoner of the angels. According to Agliè, Simon is a figure who recurs throughout history and recognizes Sophia whenever she is reincarnated.

Belbo becomes enraged over the implication that Lorenza and Agliè are lovers. Lorenza reassures Belbo that she and Agliè have never had sex and that they are merely playing games with each other. However, she also drunkenly declares that by being Sophia, she is free from the bounds of morality and has absolute freedom. Belbo pulls her away from the party, bringing her to tears.

Casaubon visits Munich to find more illustrations for the metals book. In a museum exhibit on mine tunnels, he encounters his neighbor, a taxidermist named Signor Salon. Salon explains he is there to study the underground world, which is his hobby interest. He has done similar excursions in Paris and in Rome, visiting their tunnels and catacombs. Salon explains that in Paris, the tunnel system was built to accommodate the Masters of the World.

Before they part ways, Salon asks if Casaubon ever found out what happened to Ardenti. Casaubon senses that Salon knows something about the mystery, but will not say more.

Casaubon asks Agliè about two names Salon referenced: Saint-Yves d’Alveydre and Agarttha. Agliè explains that Saint-Yves was a political theorist who was led to the King of the World’s secret residence, an underground metropolis and repository of mystical knowledge called Agarttha. Agarttha was rumored to be the Templars’ hiding place during the time of the mass arrest. Agliè suggests there is some weight to Saint-Yves’ story.

Casaubon looks for reference materials on Saint-Yves and bumps into Inspector De Angelis. De Angelis explains that he was also researching Saint-Yves out of personal interest in the Templars and Agarttha. While the Ardenti case has gone cold, De Angelis remains sensitive to any clues that could advance the investigation.

De Angelis tells Casaubon about synarchy, a political theory that combined economics, the law, and religion under three equal councils. Throughout the early 20th century, various social groups claimed to espouse synarchic ideals while also residing on opposite sides of the left-right political spectrum. Casaubon resolves this contradiction by indicating that there must be one secret society whose goal is to spread rumors that they are engaged in a massive conspiracy. Otherwise, synarchy is a convenient scapegoat for one party to slander its rivals. Before parting ways, De Angelis asks Casaubon about an organization called Tres. Casaubon does not know it.

Later, Lia suggests that De Angelis sincerely needs Casaubon’s help. She adds that the answer that would have satisfied De Angelis was that the conspiracy around synarchy is a symbol for the quest to prove the existence of God.

Casaubon visits Signor Garamond to authorize an order and sees Agliè in the secretary’s office. Garamond explains that Agliè gave him an idea to expedite the publication of Isis Unveiled: Convince the list of published Manutius authors to contribute to the series. In the hopes of persuading them to join the project, Agliè is inviting all the authors, as well as the editorial staff, to a castle in Turin to witness a Rosicrucian alchemical ritual. Agliè will take the editors to a druidic rite afterward.

Belbo suggests making a stopover in the town where he grew up, inviting along Diotallevi and Lorenza.

The group arrives at the villa of Uncle Carlo, which instantly turns Belbo nostalgic. Lorenza asks if she will get to share Belbo’s bed. Belbo gives a non-committal answer, which sparks tension between them.

Belbo recalls an occasion when fighting broke out between the Fascists and the partisans in their town, and his family was caught in the crossfire. During the battle, Carlo and Adelino made amends. Casaubon realizes that Belbo feels nostalgic for this time because the world was easier for him to understand then.

Belbo tells a story about Don Tico, the man who taught him to play trumpet. Belbo wanted to play trumpet in Don Tico’s marching band to impress his crush, Cecilia. Don Tico made him play the bombardon instead. Belbo persuaded two peers to take his place so that he could be moved to trumpet. However, Cecilia was absent from the marching band’s performance and Don Tico returned Belbo to the bombardon.

Later that evening, Casaubon is in bed when he hears Lorenza slamming a door and scratching the door to Casaubon’s room. Casaubon is tempted to accept her seduction, but tries to distract himself with thoughts of Lia instead.

The next day, Lorenza announces that she is returning early to Milan. The editors proceed to meet with Agliè and Garamond and arrive at the castle. Agliè explains that the castle grounds feature a hanging garden designed to evoke ancient spells and pre-Enlightenment logic. Casaubon is surprised to see Salon at the castle and learns from Agliè that he is a police informer.

Casaubon observes the similarity between the ritual symbols and Christian iconography. Belbo interprets this to mean that there is no difference between high culture and low culture.

As the ritual begins, several vapors intoxicate Casaubon. He becomes convinced Lorenza is present and desires him. Casaubon experiences several surreal images, including a black sunset, a golden royal wedding-turned execution, and a bloodied burn whose ashes are baked to form a young man and woman. A blinding light ends Casaubon’s vision. Agliè reassures him that while what he saw was merely a performance, it produced something.

Agliè brings the editors into the garden, where vessels containing the figures from the ritual vision are on display. Agliè suggests that the figures are living beings who are being grown to create prophecies. Casaubon finds himself yearning for Lorenza.

Casaubon roams the grounds, still looking for Lorenza. He overhears a conversation where Salon tells his companions about the extensive underground network of canals beneath Paris. The sewers contain hidden chambers with stores of treasure. All the houses in Paris can access the sewer system through hidden passages.

Casaubon is bewildered by Salon’s claims. Just then, he hears someone say that they are proceeding to a secret chamber to begin another rite.

Casaubon reports what he has heard to Agliè. Agliè explains that the rite is a Rosicrucian initiation. Though non-members are forbidden from attending it, Agliè brings his guests through a secret passage, where they see Bramanti and several men wearing emblems of the Order of the Golden Fleece. The editors observe a resemblance between the Rosicrucian ceremony and the Masonic rites. Agliè clarifies that Freemasonry is derivative of the Templar tradition. Belbo asks which tradition Agliè subscribes to. Agliè replies that he studies all traditions with scholarly distance. He adds, however, that that the derivation of Freemasonry works to the Templars’ advantage since it would allow them to hide their secrets in plain sight.

Agliè brings the editors to the druidic ritual in the woods. He explains that druidesses are invoking the androgynous cosmic being Mikil. They use a horn to conjure a fog, which obscures the center of the site. One of the druidesses runs toward the editors, then changes course to circumnavigate the cloud. Agliè soon tells the editors they are not allowed to see the rest of the ritual. He is unable to explain more about the ritual for reasons of discretion.

Casaubon returns to Milan and reunites with Lia. Because of his recent experiences, Casaubon worries that he is losing faith in scientific logic in favor of esoteric logic. Lia reassures him that his passions are getting the best of him, and that physical reality always comes before logical reality. She makes an extended analogy to the logic of the body and explains how archetypal symbols arise from the principles of the body. All meaning derives from the natural patterns that make the body feel good. Hence, the reason many cults utilize circular shapes in their iconography is that this shape evokes the sun, which benefits the body. Likewise, numerology derives from bodies, allowing every number from one to 10 to be linked to the features of the human body.

Soon after having sex, Lia reveals she is pregnant with Casaubon’s child.

Casaubon finds joy in the anticipation of his child with Lia. Following the completion of the metals book project, Signor Garamond proposes a new book project on the history of magic.

It is during this period that Casaubon, Diotallevi, and Belbo devise the Plan. A file from Abulafia entitled “Dream” suggests that Belbo immersed himself in the creation of the Plan as a distraction from the failure of his romantic life.

One day, Belbo boasts that Abulafia has the ability to generate new texts from combinations of input material. He offers to demonstrate it by taking lines from the various manuscripts they’ve collected for Isis Unveiled and synthesizing a text with the specific parameter that each line should connect back to the Templars. Belbo shows Casaubon and Diotallevi the result the next morning. While it is largely inscrutable to his colleagues, Belbo manages to grasp its conspiratorial meaning.

Diotallevi is unimpressed with the output while Casaubon suggests that it could be on par with existing Templar literature. To improve the result, he suggests feeding Abulafia less relevant information to see what connections it makes to the Templars. Belbo realizes that this will work, offering an example in the dialectic reading of car design as a symbol for Kabbalah.

Casaubon goes to Portugal for a conference and visits a Templar castle in Tomar. He is surprised to find familiar emblems linking the Templars to the other secret societies, including the Order of the Golden Fleece and the Rosicrucians. He eventually realizes that Tomar could be one of the locations Ardenti spoke of in the decrypted Templar message.

Casaubon and Belbo retrieve Ardenti’s manuscript from the archives. Casaubon reinterprets the decrypted message beginning with Tomar as the first location (the castle) and discerns that Scotland is the second location (the bread).

Belbo suggests that the third location (the refuge) is Paris and the fourth (Our Lady Beyond the River) is in Marienburg. The following week, Casaubon suggests that the fifth location (the Hostel of the Popelicans) is in Bulgaria. Belbo reasons that the interruption of the Templars’ plan occurred here, citing the invasion of the Turks. The plan would have brought the Templars back to Jerusalem by 1944, which would have served as the sixth and final location. He elaborates that because the Templars in Jerusalem wouldn’t have known about the five other groups, there was no failsafe for interruption and the plan could not resume. When Casaubon indicates that he will revisit the Rosicrucian manifestoes for clues, Belbo points out that the manifestoes are supposed to be fake, forgetting that the story they are creating around the Templars is meant to be fictional as well.

It becomes clear that Belbo believes in the conspiracy he, Casaubon, and Diotallevi are starting to devise as true. A file from Abulafia entitled “Ennoia” suggests that he remains too preoccupied with his failed romances to discern the reality of the conspiracy.

Casaubon reviews the Rosicrucian texts to see what other connections he can invent between the Rosicrucians and the Templars’ plan. He discerns that the texts were written to address the interruption of the Plan with the hopes of calling forward someone who knew how to resume it. Since the texts originated from Germany, this means that the interruption took place in the preceding location of the plan, Paris.

Belbo supplies the Gregorian calendar reform as the reason behind the interruption in Paris. Casaubon suggests that the English statesman Francis Bacon, who was rumored to be a Rosicrucian, took up the leadership of the British Templars and used the marriage between Elizabeth and Fredrick V to strengthen relations with the German Templars. This enabled them to realize the error of the interruption and rectify it by supplying the Rosicrucian manifestoes as an appeal across all of Europe.

The Thirty Years’ War made it difficult for the appeal to achieve its purpose. The English Templars personally attempted to expand the appeal to France, but suffered the interference of statesman Cardinal Richelieu. This exacerbated the chaos surrounding the Templars throughout the early 17th century.

The Garamond editors conclude that the Templars’ plan is meant to provide a unified explanation for all the mysteries that the Templars’ successors are devoted to. They add that once assembled, the Templars’ secret message would reveal a map. Diotallevi marvels at this conclusion, remarking that they are rewriting world history.