Twenty-two-year-old college student Manuel finds his life spiraling into a chaotic web of guilt and emotional alienation in Mexico City. While his best friend, Gregorio—a deeply troubled young man suffering from severe schizophrenia—is confined to a psychiatric institution, Manuel begins a highly volatile, secret extramarital-style affair with Gregorio’s girlfriend, Tania. Consumed by the physical intensity of their mutual betrayal, the couple hides their relationship until a newly released Gregorio discovers the truth and commits suicide. In the wake of the tragedy, Manuel inherits a weathered box left behind by his late friend, filled with cryptic messages, encoded letters, and disturbing clues. As Manuel and Tania attempt to decipher Gregorio's final psychological trap, their relationship fractures under the weight of severe paranoia, driving them down a dark descent into madness and mutual distrust.