Act One
King Heinrich has come to Antwerp to raise an army in order to fight the Hungarians. Before doing so,
however, he must preside over a court hearing: Friedrich of Telramund has charged Elsa, daughter of the deceased Duke of Brabant, with the murder of her brother Gottfried. Elsa says nothing with regard to
the accusations. Instead, she talks about a knight who appeared to her in a dream and promised to help her.
A trial by combat is supposed to decide the dispute. Elsa designates the knight whom she has dreamt about
as the champion of her innocence. He is called twice, but the only answer is profound silence.
At last, Elsa’s prayer is heard: drawn by a swan, the man of her dreams appears. He is willing to fight for Elsa and offers her his hand in marriage under the condition that she never ask him to reveal his name or descent. Elsa promises to respect his wishes. The stranger defeats Friedrich of Telramund, but spares his life.
Act Two
Telramund and his wife Ortrud have been outlawed. While the strange knight’s victory is celebrated in the castle, Ortrud once again convinces her husband of the legitimacy of his charge and persuades him to join her in exacting revenge.
Telramund is to accuse the stranger of sorcery and deception, while Ortrud, for her part, will inveigle Elsa into doubting the correctness of refraining from asking her future husband to reveal his identity.
With feigned kindness, Ortrud insinuates herself into the confidence of an unsuspecting Elsa.
The following morning, Elsa is being conducted to her wedding when Ortrud interrupts the ceremony
and challenges her right to precedence: Telramund enjoyed the greatest esteem in Brabant before being
outlawed by a false court. By contrast, Elsa cannot even address her future husband by name.
Telramund accuses the strange knight of sorcery and demands that he reveal his identity. The knight, however, refuses: he is obliged to answer that question only if asked by Elsa, but Elsa confirms her unconditional
trust in the unknown man.
Act Three
In the bridal chamber, the lovers find themselves alone together for the first time. Yet the doubts raised by Ortrud leave Elsa no peace. The desire to find out her husband’s name and secret grows ever stronger. Despite all warnings, she finally asks the fateful question.
With his sword drawn, Telramund forces his way into the room and is killed by the unknown knight.
The next morning, the knight charges Telramund with attempted murder and accuses Elsa of having broken her promise. Now he is forced to disclose his secret: he is Lohengrin, son of Parsifal, King of the Grail. The swan is already approaching to take him back whence he came. A triumphant Ortrud reveals that it was she who transformed Elsa’s brother into the swan. Lohengrin liberates Gottfried from his alien guise and appoints him as the new ruler.