A philosophical allegory regarding the human situation and the mystery of life. The story focuses on the fictional Segismundo, Prince of Poland, who has been imprisoned in a tower by his father, King Basilio, following a dire prophecy that the prince would bring disaster to the country and death to the King. Basilio briefly frees Segismundo, but when the prince goes on a rampage, the king imprisons him again, persuading him that it was all a dream.

After the death of his parents, Juan goes into an adventure to find Captain Escalaborns to whom he must deliver the map of a treasure to be searched together.

A work of Valle-Inclán, the story takes place in Galicia in the early twentieth century. To escape poverty, the wife of a sacristan uses a hydrocephalic child as a sideshow attraction. This causes a confrontation with her sister-in-law.