Portugal is feeling the after-effects of a storm of anti-religious sentiment and the violent overthrow of the monarchy and the government in the 5 October 1910 revolution.

Another flash of lightning causes them to run straight into an unusual "cloud of light" surrounding a little tree on which a mysterious Lady stands.

Speaking slowly and gently, the Lady asks them to return on the 13th of each month, and to offer their sufferings to God for the salvation of sinners.

Later, they encounter their agnostic friend Hugo da Silva (Gilbert Roland), who tells them it is best not to reveal the vision to anyone else, but of course on returning home, Jacinta immediately divulges her sightings.

Jacinta and Francisco's parents quickly believe the story, but Lúcia's mother reacts with disgust and subjects her daughter to emotional and physical abuse.

On October 13, when the Lady promised "a sign that will make them believe", about forty thousand people arrive, waiting through a torrential downpour.

A short epilogue, circa 1951, shows the huge basilica where the tree once stood, and a million people outside paying homage to Our Lady of Fátima.

At the end of the film, inside the new basilica (where the Cova da Iria once was), Lúcia is now a nun praying before the tomb of her cousins, the converted Hugo at her side.