Archibaldo de la Cruz, a wealthy Mexican man, begins a tale by telling a nun a memory from his childhood, a memory that still haunts him with a sense of dangerous power. During the upheaval of the Mexican Revolution, his indulgent mother entrusts him with a special music box, and his stern governess, The Governess, warns that it can unleash death on his enemies. To test this ominous claim, Archibaldo winds up the box, and tragedy follows in a flash: the governess is struck by a stray bullet, fueling a chilling belief that he has killed her. Emboldened by the illusion of control that such thoughts grant him, he goes so far as to threaten a nun with a straight razor; the nun flees, only to plunge down an open elevator shaft. When a judge investigates the strange incident, Archibaldo confesses to killing the nun, and hints that she is not his first victim.
With the confession, Archibaldo then spins a second, longer story for the judge. A few weeks earlier, he sees the music box in an antique shop, where a beautiful woman named Lavinia, and her elderly fiancé, prowl over it. He persuades the shopkeeper to sell it to him, insisting the box once belonged to his mother and was stolen during the Revolution. Back home, he replays the box, and a shaving cut he gives himself bleeds—triggering vivid visions of the governess’s death. His obsession deepens as he crosses paths with Carlota Cervantes, a young woman he admires. Outside her home, she is with her married lover, the architect Alejandro Rivas, and Archibaldo’s growing fixation becomes a source of tension rather than romance: Carlota’s mother urges distance, and the relationship seems fragile.
At a gambling parlor, Archibaldo spots Patricia Terrazas and follows her when she leaves in a heated mood. Their encounter leads him to a moment of danger, but Patricia’s own admission later reveals she was trying to provoke jealousy in her lover, Willy Corduran. The next day, a police detective informs him that Patricia has apparently taken her own life. Carlota, wary of Archibaldo’s advances, avoids his calls, and he heads to a bar where he glimpses Lavinia again—this time seemingly surrounded by flames emanating from her drink. Lavinia is not just a pretty face; she is linked to the life Archibaldo imagines for himself, and she agrees to meet him in his studio under the pretense of modeling.
Carlota finally breaks away from her lover and contemplates a future with Archibaldo, though she must navigate an obstacle: Alejandro’s resistance and a desire for a divorce from his wife. The day Lavinia is set to visit, Archibaldo sends away his servants, presenting the studio as a private sanctuary. Lavinia arrives, and the two engage in a dangerous game: she pretends to be compliant, but swaps clothes with a mannequin to mock him. Archibaldo, momentarily fooled, tries to kiss what he thinks is Lavinia, only for her to kiss him back as the ruse falls away. In a bold twist, Lavinia removes her own clothes but keeps the mannequin’s expensive garments, further fueling the tension between desire and manipulation.
A ring of disruption follows when a group of tourists unexpectedly arrives at the studio, and Lavinia claims she invited them for a tour. Archibaldo’s anger boils as he watches the living woman and the mannequin he bought share his world. He melts the mannequin in a kiln, a symbolic act that reveals how far he will go for power, love, and release from his own inner ghosts. Carlota’s mother arrives soon after to announce that Carlota has accepted Archibaldo’s proposal, though her own feelings appear mixed and uncertain.
As the wedding day approaches, Archibaldo receives a letter directing him to Alejandro’s apartment. From the outside, he witnesses Carlota enter the space and Alejandro close the blinds. Carlota pleads for no interference, but Archibaldo senses that something remains unsettled between them. He even entertains a dark fantasy of shooting her on their wedding night, only to have his plan foiled when Alejandro fires at her just after the ceremony and she dies. After hearing Archibaldo’s confession, the judge concludes that while Archibaldo has the capacity to become a criminal, he has committed no definite crime. Still tormented by the deaths that haunt the lives around him, Archibaldo returns home, plays the music box once more, and then stops it, discarding it into a lake. Relief washes over him. In a chance meeting, he runs into Lavinia again and learns she did not marry after all. They walk away together, facing an uncertain but shared future.
