In a deserted mountainous area, not far from the court of the Polish king, Rosaura, a noble lady dressed in a man’s dress, and her servant, lost their way. The night is approaching, and there is no light around. Suddenly travelers distinguish in the twilight a tower, from behind the walls of which they hear complaints and lamentations: it curses its fate encased in the chain Sehismundo. He complains that he is deprived of freedom and those joys of being that are given to everyone born in the world. Having found the door of the tower unlocked, Rosaura and the servant enter the tower and enter into a conversation with Sehismundo, who is struck by their appearance: in his entire life the young man saw only one person – his jailer Clotaldo.
The sound of their voices comes from the asleep Klotaldo and calls the guards – they are all wearing masks, which greatly affects the travelers. He threatens to death uninvited guests, but Sekhzmundo resolutely intervenes for them, threatening to end his life if he touches them. The soldiers take Sekhzmundo away, and Clotaldo decides, taking away the weapons from the travelers and blindfolding them, to take them away from this terrible place. But when Rosaura’s sword hits him, something strikes the old man in him, Rosaura explains that the man who gave her this sword (she does not name her name), ordered to go to Poland and show her to the most notable people of the kingdom, from whom she will find support –
Left alone, Clotaldo remembers how he gave this sword once to Violante, saying that he would always help someone who brought it back. The old man suspects that the mysterious stranger is his son, and decides to seek advice from the king in the hope of his rightful trial. For the same appeal to Basilio, the King of Poland, Infanta Estrella and Prince Muscovy Astolfo. Basilio is their uncle; he himself has no heirs, so after his death the throne of Poland must go to one of his nephews – Estrella, the daughter of his elder sister Clorina, or Astolfo, the son of his younger sister, Resizmunda, who was married in far-away Muscovy. Both claim this crown: Estrella because her mother was Basilio’s elder sister, Astolfo – because he is a man. In addition, Astolfo in love with Estrella and invites her to marry and unite both empires. Estrella is not indifferent to the beautiful prince, but she is embarrassed that on his chest he wears a portrait of some lady who does not show anyone. When they turn to Basilio with a request to judge them, he reveals to them a thoroughly concealed secret: he has a son, the legitimate heir to the throne.
Basilio all his life was fond of astrology and, before his wife was to be relieved of the burden, calculated by the stars that his son was destined for a terrible fate; he will bring death to his mother and all his life will sow death and strife around him and even raise his hand to his father. One of the predictions came true right away: the boy’s birth was worth the life of Basilio’s wife. Therefore, the king decided not to endanger the throne, fatherland and his life, and deprived the heir of all rights by imprisoning him in prison, where he was Sekhimzundo, and grew up under the watchful eye of Clotaldo. But now Basilio wants to dramatically change the fate of the Crown Prince: he will be on the throne and will have the opportunity to rule. If they are guided by good intentions and justice, he will remain on the throne, and Estrella,
Meanwhile, Clotaldo leads to King Rosaur, who, touched by the participation of the monarch, tells that she is a woman and found herself in Poland in search of Astolfo, connected with her by the bonds of love – it is her portrait that the Prince of Muscovy wears on his chest. Clotaldo gives every support to the young woman, and she remains at the court, in the retinue of the infantile Estrelia under the name Astrea. Clotaldo, on the orders of Basilio, gives Sehismundo a soporific drink, and, sleepy, he is transported to the palace of the king. Here he wakes up and, realizing himself as a lord, begins to create outrages, like a wild beast burst out: with everyone, including the king, rude and harsh, throws off a balcony from the balcony dare to contradict his servant, trying to kill Clotaldo. Patience Basilio comes to an end, and he decides to send Sehismundo back to prison. “Will you wake up, where did you wake up before”
Confusion Sehismundo, when he wakes up in shackles and animal skins, can not be described. Clotaldo explains to him that everything that he saw was a dream, like the rest of his life, but, he says instructively, “and in dreaming, goodness is good.” This explanation makes an indelible impression on Sekhimzundo, who now looks at the world from this angle.
Basilio decides to hand over his crown to Astolfo, who leaves no claims to Estrella’s hand. Infanta asks her new friend Astrea to get for her a portrait that Prince Muscovy wears on his chest. Astolfo recognizes her, and between them there is an explanation in the course of which Rosaura at first denies that she is she. Nevertheless, she manages to wrest from Astolfo her portrait – she does not want another woman to see him. Her grievances and pains have no limits, and she sharply reproaches Astolfo for treason.
Upon learning of Basilio’s decision to give the crown of Poland to the Prince of Muscovy, the people are raising the uprising and releasing Sehismundo from the dungeon. People do not want to see a stranger on the throne, and the rumor about where the Crown Prince is hidden has already flown around the kingdom’s limits; Sekhimzundo leads a popular revolt. The troops under his leadership defeated the supporters of Basilio, and the king was already ready for death, giving himself at the mercy of Sehismundo. But the prince changed: he changed his mind a lot, and the nobility of his nature prevailed over cruelty and rudeness. Sekhimzundo himself falls at the feet of Basilio as a loyal subject and obedient son. Sehismundo makes one more effort and transcends his love for Rosaur for the sake of the feeling that the woman feeds for Astolfo.
The prince of Muscovy tries to refer to the difference in their origin, but then the noble Clotaldo enters into the conversation: he says that Rosaura is his daughter, he recognized it by the sword that was once given to her by her mother. Thus, Rosaura and Astolfo are equal in their position and there are no more barriers between them, and justice triumphs – Astolfo calls Rosaur his wife. The hand of Estrella goes to Sekhimzundo. With all Sekhzmundo, he is friendly and just, explaining his transformation by being afraid to wake up again in prison and wants to enjoy happiness like a dream.