The King is alone in church. In a wonderful aria he sings of his sadness that his wife does not seem to love him. The Grand Inquisitor comes in. He is very old, and blind. The King tells him about his son, and asks the Inquisitor whether Carlos should be forgiven or sentenced to death. The Inquisitor answers that it is Rodrigue who should be killed. The king dares to disagree. The Inquisitor tells the King that he is not giving his heart to God. The Inquisitor goes.