Elisabeth kneels before the tomb of Charles V. She sings of her lost youth in France (some of the music from Act I comes back here). She prays for peace. Elisabeth and Carlos then meet for the last time (their third duet in the opera) and wish for happier times. The King and the Inquisitor have been hiding. They now appear and grab Carlos. The guards are told to grab him, but Carlos defends himself. Suddenly the voice of Charles V (or a monk in disguise) is heard. He takes his grandson into the safety of the cloister.