Segismundo has been a prisoner in a tower all his life, he doesn't know the reason. When he was born his father, the king, predicted that he would be a tyrant, so he locked him up. Now that the king is old he decides to free him to see his true nature and should he fulfill the prophecy he intends to lock him up again and make him believe everything was a dream.
I read this play more times that I can count. This Oedipus type of story has some⬇️