Fidelio.

Leonore disguises herself as a man, "Fidelio," to infiltrate a prison and rescue her husband, Florestan, unjustly imprisoned by the tyrant Pizarro. Gaining the trust of the jailer, Rocco, and his daughter, Marzelline—who unknowingly falls for Fidelio—Leonore’s courage is tested when Pizarro orders Florestan’s execution. In a climactic moment, she reveals her identity and saves Florestan just as the king’s minister arrives, restoring justice. The opera celebrates themes of love, sacrifice, and freedom.