A Life in the Balance

In Mexico City, police captain Saldana and Lt. Fernando are frustrated by the stabbing murders of six attractive women, to which there are no witnesses. The latest murder occurs in the early evening at a large apartment building, and ten-year-old Francisco "Paco" Gomez passes by the police investigating the crime on his way home. Paco is greeted by his devoted father Antonio, a widowed musician who has passed on his love of music to his son. Antonio's poverty rankles his neighbors, Andres and Carmen Martinez, who want custody of Paco, and Antonio reluctantly considers their offer. Unknown to Paco, Antonio's temper caused him to lose his job, and he has been pretending to go to work every night so that Paco will not be disappointed. Paco longs for a guitar, and despite his lack of funds, Antonio promises that he will buy one. Antonio arranges to meet Paco that night at a nearby café and gives him permission to go to the roof to watch the fireworks in celebration of the day's festival. Antonio then stops by the apartment of his former girl friend, dancer Carla Arlotta, to ask for repayment of a loan he made to her so that he can buy Paco's guitar. Antonio and Carla briefly argue, but she accepts his declaration that their relationship is over and gives him 500 pesos. After Antonio leaves, a stranger enters Carla's apartment and kills her. Carla's body is soon discovered, and Paco sees the murderer leave while various neighbors find Antonio's lunchbox in Carla's apartment and proclaim that he must be the killer. Determined to prove that his father is innocent, Paco follows the real murderer, but his pleas for help are ignored. Meanwhile, Antonio, who is unaware of Carla's death, goes to the pawnshop of Doña Lucrecia to buy a second-hand guitar. There, Antonio meets the lovely Maria Ibinia and helps her to sell a ring to Doña Lucrecia. Charmed by Antonio, Maria wanders with him through the streets crowded with revelers and floats. Back at the apartment building, Saldana and Fernando issue an arrest warrant for Antonio, and Saldana also agrees to grant custody of the missing Paco to the Martinezes when he is found. On the street, Paco breaks a police call box to attract attention, but when he is again ignored, he follows the killer onto a bus. Paco falls asleep during the ride, and when he hurriedly exits the bus to find the stranger, the man grabs him. Vaguely recognizing Paco, the man decides to accompany him to the café where he is to meet Antonio, in order to determine if the boy is lying about following him. Paco is terrifed as the man grips his arm and marches him to the café, where Antonio and Maria are falling in love as they dance. Suddenly, Antonio realizes that he has misplaced Paco's guitar, and after he leaves the café to find it, Paco and the man arrive. Not seeing Antonio, the man decides that Paco is a liar and should be punished for his sins. When Paco inadvertently reveals where he lives, the stranger realizes that Paco saw him exiting Carla's apartment. Not knowing that it is Paco, Maria sees a young boy being dragged away by an American man, while at the station, policemen complain about the call boxes that Paco continues to break. Unaware that someone is seeking help, the police assume that vandals are responsible and ignore the incoming calls. The deluded murderer, who believes that God has ordered him to return the women he has killed to heaven, forces Paco to accompany him to church, where he prays over Paco's fate. Meanwhile, Antonio is arrested and brought to Saldana and Fernando, with whom he pleads to find Paco. Antonio's concern for Paco touches Fernando, who comes to believe Antonio's protestations of innocence. Maria is also brought to the station and castigates Saldana for pre-judging Antonio, especially after Doña Lucrecia verifies that he was in her shop at the time of Carla's death. When Antonio sees a marble that was used to shoot out a call box, he recognizes it as one of Paco's, and realizes that Paco could have seen the killer. Soon after, Paco's coat is found by one of the broken boxes, and Fernando deduces that Paco has been trying to summon help. While the police search the city, a grief-stricken Antonio waits with Maria at the station, until early the next morning, when he accurately predicts that Paco will be hungry. By calling every restaurant in the area, the police then deduce Paco and the killer's location and move in. Seeing the police coming, the stranger hijacks a bus and crashes it near the university. Dragging Paco along with him, the murderer is pursued by the police and Antonio through the empty campus. Finally cornered, the killer holds Paco at knife point, but Antonio wrestles with him just as Fernando shoots him. Standing over the man's body, Antonio wonders how people can build beautiful places such as the university while also being capable of committing such evil. Paco states that the man just wanted to be his friend, and Fernando comments that loneliness can drive men insane. Antonio then introduces Paco to Maria, who gratefully states that she has been searching for both of them all of her life.