After three days of relentless rain, Pelayo returns from throwing into the sea the crabs that were infesting his home and leaving behind an unpleasant odor, possibly causing his newborn baby’s sickness. He stumbles upon a bedraggled old man with enormous wings sprawled face-down in his courtyard. Fear and curiosity overcome Pelayo and his wife, Elisenda, as they grapple with the inexplicable presence. The man, dressed in tattered clothes and speaking an unknown language, is initially perceived as a castaway.
However, a neighbor who holds fervent religious beliefs declares him to be an angel. Pelayo pays no heed to the neighbor and locks the old man in the chicken coop in his courtyard. A day later, the rain stops, and the baby gets better. Pelayo and Elisenda think about sending the old man to the ocean with food and water for three days, relying on nature to take care of him.
By then, the news of the "angel" had spread like wildfire, drawing the entire town to Pelayo's courtyard. Father Gonzaga, the local priest, arrives, surprised by the news of an angel but hoping to shed light on the mystery. He attempts to communicate with the man using Latin, traditionally associated with the divine. However, the man's silence and lack of comprehension cast doubt on his angelic identity. Despite Father Gonzaga's pronouncements, the townspeople remain convinced.
News of the "angel" attracts pilgrims from afar, each seeking solutions to their individual problems. A woman obsessed with counting her heartbeats seeks relief, while an insomniac pleads for respite from the noise of the stars. The man, however, remains impassive, offering no answers or solace. He also ignores those who treat him as a spectacle, staying still even when they pluck his feathers and throw stones at him. He is infuriated only when he is eventually seared with a branding iron. He flaps his wings vigorously and yells in his incomprehensible language. This outburst does little to alter the townspeople's perception.
The frenzy eventually reaches a peak, leading Elisenda to suggest the construction of a fence and the implementation of a five-cent admission fee. Soon enough, Pelayo and Elisenda start finding themselves drawn to the financial gains from the situation.
The excitement around the "angel" soon begins to fade when a new spectacle arrives in town: a traveling carnival showcasing the "spider woman," a human transformed into a tarantula “the size of a ram” with a woman’s head as punishment for disobeying her parents. The townspeople, captivated by this new marvel, lose interest in the "angel," leaving him abandoned and forgotten. Pelayo and Elisenda, however, have accumulated abundant wealth from the admission fees they had charged; Pelayo is also able to quit his job and build a new, larger house.
The old man continues to stay with them in the chicken coop for many years as their son grows older. Despite several warnings to stay away, the child goes into the chicken coop, and the two fall ill with chicken pox. When the child grows up, the dilapidated chicken coop collapses, prompting the old man to wander from room to room in the family’s home, much to Elisenda’s annoyance. He then moves into the adjacent shed.
Winter brings illness to the old man, but he miraculously recovers and regains his strength. His missing feathers grow back, and he begins humming sea shanties at night. One day, surprisingly, the old man attempts to take flight. He struggles initially but, eventually, soars into the sky and disappears over the horizon. Elisenda, witnessing his departure, feels a mix of relief and sadness for both herself and the old man.