The plot of Prince Prigio begins with the introduction of a queen who does not believe in fairies. After many childless years, she and the king finally had a boy, Prigio. When the queen refused to invite the fairies to the christening, none of the nobles would attend, and so the king and queen were alone when the fairies arrived and presented the child with gifts. Among the gifts were a never-empty purse (the purse of Fortunatus), seven-league boots, a cap of darkness which would make him invisible, a wishing cap, a magic carpet, and also beauty, courage, and luck, but the last fairy decreed, "My child, you shall be too clever!"

This would have pleased the queen, but she did not believe it. She had all the items swept into a lumber room.

The prince grew up to be too clever. He would argue with everyone and knew better than everyone. He had two younger brothers, neither of whom was clever, and both of whom were liked; they fell in love with their cousins. The king particularly disliked Prigio, fearing he would claim the throne, and wanted to be rid of him. One day, a firedrake appeared in the country; the king was sorry that it would kill his second son as well as his first before the youngest son killed it, but he would sacrifice him to be rid of Prigio. Prigio, like his mother, refused to believe in its existence and reminded him that it was the youngest son who triumphed, so they should send him at once.