The following version of this book was used to create the guide: Moreno-Garcia, Silvia. Silver Nitrate. Del Rey, 2023.

In Mexico City in the 1990s, Montserrat Curiel works as a sound editor at a film studio called Antares, where she struggles to keep up with the outlandish demands of the various male directors and supervisors that surround her. She also harbors romantic affection for her perpetually unavailable best friend, a former television star named Tristán Abacal whose career has faded in the wake of a tragic car accident. One day, Tristán discovers that he lives in the same building as Abel Urueta, a cult horror director from México's Golden Age of cinema, and decides to forge a friendship with him. Abel takes a quick shine to both Montserrat and Tristán and begins regaling them with stories that his career has been cursed because his final horror film, Beyond the Yellow Door, was never finished, a consequence of a number of mysterious production issues that plagued it. As Tristán struggles to get his career back on track and Montserrat seeks forms of income outside Antares, the pair become interested in probing further into Abel's past for information.

Montserrat begins to question Abel further about Beyond the Yellow Door and quickly realizes that its co-creator, a white supremacist named Wilhelm Friedrich Ewers, was an occultist who believed that in completing the film he would be able to cast a spell to restore himself back from ill health. Abel urges Montserrat and Tristán to help him complete the film in order to undo its curse, something they reluctantly agree to do. After completing the dubbing on the film's final scene, each member of the trio begins to experience a spell of good luck, but it becomes clear that this fortune comes at a cost when Tristán begins having visions of his former girlfriend, Karina, whose death during Tristán's car accident has long haunted him with guilt and ruined his career. Montserrat and Tristán confront Abel, who explains that there may have been side effects from the completion of the spell and promises to speak to his old friend José about the strange happenings that have plagued Tristán. Montserrat begins to explore Ewers' book, The House of Infinite Wisdom, and discovers a secret letter inside of it explaining that Ewers came to México from Nazi Germany and was as interested in eugenics and white supremacy as he was in magic; meanwhile, Abel has a vision that Alma Moreno, the benefactor of Beyond the Yellow Door, intends to kill him as retribution for casting the spell.

Sure enough, Montserrat finds Abel murdered that night in his apartment, and has the distinct impression that a malignant spirit is lingering in the room where his body is found. She convinces Tristán to begin poking around the lives of the other people involved in the creation of Beyond the Yellow Door—Alma Montero, Clarimonde Bauer, and José López—and the pair quickly learn that the old feud between Alma and Clarimonde is alive and well. Alma bankrolled Beyond the Yellow Door because Ewers promised the spell would bring her eternal youth, but instead he replaced her with the younger and more beautiful Clarimonde in order to satisfy his own whims. Montserrat goes to the abandoned building where Clarimonde once ran an editing agency, Ediciones B, and encounters a spirit in the building that she is certain belongs to Ewers himself. Meanwhile, Tristán botches his first acting appearance in years when Karina appears to him in a mirror and causes him to flee the scene.

Tristán wants to destroy Ewers' writings and never examine the issue further, but Montserrat refuses, insisting that they need to undo the damage they have created by casting the spell in the first place. Tristán meets with Marisa Montero, who insists that he needs to deliver Ewers' possessions to her so that she can destroy them; the next night, when Montserrat and Tristán meet with Clarimonde, she attempts to pressure them into handing over the materials, too, and is only stopped when Montserrat uses her newfound knowledge of magic to cast a protective spell against her. Tristán urges Montserrat to give up the materials to one woman or the other, but Montserrat remains suspicious that neither of them is actually interested in defeating Ewers. These suspicions prove correct when Montserrat and Tristán are attacked by both Alma's and Clarimonde's followers and are saved only by the intervention of José López, who comes to their rescue at the eleventh hour. José explains that Alma has sustained Ewers' spirit for years by using the magic to make herself appear younger and masquerade as "Marisa," then admits that he worked with Alma years before to help arrange for Ewers' murder.

José explains to Montserrat and Tristán that the only way to defeat Ewers is to screen the movie with the collection of runes that were intended to accompany it; in order to ascertain what those runes are, it is necessary for someone to commune with Abel's spirit. José fingers Tristán for this responsibility because of his ability to see Karina; through Tristan resists at first, he ultimately agrees, and successfully receives the runic sequence from Abel. However, the séance is interrupted by Ewers, who attacks and wounds José before Montserrat is able to dispel him. José sends Montserrat and Tristán to retrieve the copy of the film from Antares, where they kill a vengeful Alma with help from Ewers' spirit before being captured by Clarimonde and her followers. Montserrat convinces Ewers that she intends to help free him, then takes advantage of his trust to interrupt the resurrection ritual Clarimonde has arranged in order to cast her own runic sequence instead. She and Tristán successfully defeat Ewers, escape the burning Ediciones B building, and connect romantically in the novel's final pages.