The poem revolves around three brothers—Don Juan, Don Diego, and Don Pedro—who strive to capture the mysterious Adarna bird, which perches on the tree of Piedras Platas at Mount Tabor. Any of the brothers must capture the bird to save their father, King Fernando, who suffers from a sickness that only the the song of the Adarna can cure. The reach maturity and are trained in combat, as expected of any prince. However, this not enough for the challenge to come. Both Don Diego and Don Pedro fail to seize the bird and consequently turn to stone when they fall asleep due to the Adarna's song and are hit with its droppings. Don Juan, however, is different. He discovers the secret of the Adarna when he helps an old leper, whom he encounters on his journey. The leper gives him magical items to capture the bird and save his two brothers. However, Don Pedro and Don Diego betray Don Juan. They steal the Adarna and almost kill their brother, leaving him trapped in a well. But Don Juan, with help from Donya Maria, escapes and is able to journey to the land of Reino de los Cristales. Don Juan falls in love with Maria as well as her two sisters: Donya Leonora and Donya Juana. Even when the prince is willing to marry any of the sisters, he undergoes a series of trials by King Salermo. Don Juan, again, succeeds and is married to Donya Maria. They live happily in the kingdom, which they inherited. Meanwhile, the Adarna bird reveals the treachery that Don Juan suffered. It seems that it was used to highlight the fantastic adventures of the princes in various lands.