Fortuna and Constanza approach the sleeping Scipio and offer to accompany him through life. However, first he has to choose between Fortuna, the provider of the world's good things, and the reliable, trustworthy Constanza.
Scipio asks for time to think. Neither in his heart nor mind can he take in what has happened, nor can he choose.
Fortuna and Constanza permit him to ask questions: he wants to know where he is. He fell asleep in the kingdom of Massinissa, but now has no idea of where he is. Fortuna tells him that he is in the Temple of Heaven. The magnificent lights are the stars against the blue background of the universe. He can hear the music of the harmony of the spheres.
Scipio asks who creates this harmony. Constanza replies that the power behind it moves the spheres like strings on a zither, finely tuned by hand and ear. Scipio responds by asking why this sound is inaudible to mortals on earth. Constanza explains that this is due to the inadequacy of their senses; looking at the sun, they see only the glare, whilst hearing a waterfall, they know nothing of its destructive power. Scipio then asks who dwells in this eternal world. Fortuna indicates an approaching cortege - heroes, his forefathers, Rome's greatest sons. Scipio sees the dead Publius and asks if dead heroes live here. Publius assures him that the light of immortality resurrects the body, freeing it from the burden of mortality. He who has thought of, felt for and devoted himself to others will live forever; those who have lived only for themselves are not deserving of immortality. Scipio goes to seek his father. He is delighted to find him, but surprised when it appears that this joy is not mutual. His father Emilio tells him that joy in heaven is complete, because it is not accompanied by suffering; he points to the Earth, small and miserable and covered in cloud, the home of mad misguided people, indifferent to other's pain.
Aghast at the sight of the Earth, Scipio begs his father to be allowed to remain in the eternal land. However, he is told by Publius that he has a great mission to complete on Earth - to destroy an enemy, after making his choice between Constanza and Fortuna.
Scipio asks Fortuna what kind of help she can offer him in completing his task. She tells him of her power to destroy and create, to corrupt innocence and empower evil. Who can resist her? Constanza says that only she can bestow the power of loyalty. Fortuna cannot go beyond the limits dictated by Constanza. Virtue can only occasionally be defeated by violence, while evil deeds, unlike good ones, are transient. Fortuna can manage rare strikes, but cannot deprive heroes of hope and faith. Thus Scipio chooses Constanza, braving Fortuna's anger unafraid, because the eternal kingdom is dearer to his heart.
Fortuna, furious, calls plagues down as vengeance on Scipio. He however keeps his courage through a foul storm. He reawakes in the kingdom of Massinissa, feeling the presence of Constanza beside him. The moral behind his dream was a hymn of praise to the eternal virtues offered by heaven, a model for all those who believe in God. In the final scene Licenza praises Scipio's choice and explains that the real protagonist of the play is not Scipio, but the dedicatee - Prince-Archbishop Hieronymus (Girolamo) Graf von Colloredo.