Act I
The brothers Chrudoš and Šťáhlav fight over the inheritance of their late father’s estate. Radmila, their sister, asks Princess Libuše to act as an arbiter. The young girl Krasava reveals that she is it to blame for the sudden hostility that has arisen between the brothers. Libuše assures Radmila that the Gods will help to resolve the strife.
At a gathering of elders, Chrudoš and Šťáhlav accuse each other of deceit and despotism. Radovan and Lutobor – Krasava’s father and the brothers’ uncle respectively – voice their opinion that such dangerous disagreements can only be settled when the nation is co-led by a man.
Libuše calls on the brothers to argue their cases. As the elder brother, Chrudoš demands to inherit everything, whereas Šťáhlav commits his fate to the judges. Radovan announces the court’s decision – the brothers should reconcile and administer the inheritance together. Chrudoš refuses to acknowledge the verdict of the court as it is headed by a woman. To maintain the peace, Libuše decides to share her rule with a man. She chooses Přemysl, a farmer from Stadice, to be her husband, and her subjects receive the statement with joy.
Act II
Lutobor, Krasava, Radmila and Šťáhlav arrive at a burial-mound in the forest to settle the dispute with Chrudoš. Krasava tries to assuage her father’s anger at her having caused the strife – unable to make Chrudoš openly profess his affection for her, she decided to provoke him by pretending to be attracted to Šťáhlav. Lutobor vows to forgive his daughter on condition that she reconciles the two brothers. Chrudoš initially dismisses Krasava’s explanation but is ultimately moved by her words. He casts aside his wrath, and makes peace with Krasava and Šťáhlav alike.
In a village, peasants revel in merry song as they gather the final crops of the harvest. Přemysl, their landlord, is absorbed in thoughts of Libuše, whom he loves, before announcing the start of the harvest festival. Sitting in the shade of a lime tree, he admires its beauty, strength and dignity, which should serve as an example to the entire nation. Přemysl’s contemplations are cut short by the sound of an approaching royal delegation. Radovan conveys to him Libuše’s intention to make him a prince and for him to take the princess as his bride.
Act III
Happy to hear that the brothers have reconciled, Libuše forgives everyone for their errors. Chrudoš, however, is afraid that Přemysl will take revenge on him for having offended the princess. Šťáhlav and Lutobor try to convince Chrudoš to curb his quick temper, but it subsides only after Krasava asks him to pledge fealty to the new prince in the name of their love.
Libuše welcomes Přemysl as her husband, and prays to the Gods to bless them. The prince calls on Chrudoš to apologise for having slighted his wife. Chrudoš initially refuses but then surrenders. As he is about to kneel before the royal couple, Přemysl offers him a fraternal embrace. Libuše thanks the Gods, believing that they will continue to grant favour to her people. Suddenly, she is entered by a prophetic spirit, and the future of the nation unfurls before her very eyes. She anticipates times of suffering and servitude ahead and hopes that the Czech nation will never yield to evil of any form.