Before his death the Duke of Brabant made Friedrich of Telramund guardian of his children, Gottfried and Elsa. Telramund married Ortrud after Elsa turned him down. King Heinrich has come to raise troops for an imminent war. Telramund, encouraged by Ortrud, accuses Elsa of murdering her brother. The King questions Elsa who, instead of defending herself, describes a Knight, a stranger, who appeared in a dream. This Knight shall fight for her. The King proclaims that the matter will be settled by God. Telramund shall fight a duel to determine whether Elsa is guilty or innocent. The Herald calls for someone to champion her cause. At last, the knight from Elsa’s dream appears and offers her his life, demanding her love and trust in return. "You must never ask me, nor try to discover, from whence I came nor what my name and lineage are." Telramund's beaten in the duel but his life is spared. ACT 2 Ortrud wants revenge. Telramund, her tool, has failed. He wasn't judged by God but is a victim of deception. The unknown knight must possess evil powers, which can only be broken by wounding him or persuading Elsa to ask the forbidden question. She urges Telramund to join her in taking revenge against Elsa and her champion: "She's mine, her knight belongs to you." Ortrud approaches Elsa, feigning friendship, warning her not to trust the stranger. Elsa takes her in. Telramund, who has seen everything, is certain that he will now succeed in taking revenge on the man who defeated him. In the minster. Otrud stands in Elsa’s way, demanding that the bride of a man without a name owes her precedence. A hero cannot be pure and noble if his lineage is secret. Elsa’s knight and the King arrive but Telramund bars their way, accusing the stranger of deceit and black magic and asking what his name and lineage are. The Knight says there's only person he must answer. The couple enter the minster to be married. ACT 3 Their wedding night: Elsa has doubts about her husband’s loyalty - she is frightened he might leave as quickly as he appeared. When she asks the forbidden question Telramund and his men break into the room. Telramund is killed. The knight orders that his body be taken before the King, where he will answer Elsa’s question. "I was sent to you by the Holy Grail: my father Parsifal wears its crown, I am his knight and Lohengrin is my name.” If a Knight of the Holy Grail is sent forth to fight for virtue, he must remain unknown or leave the land of men. Lohengrin takes his leave from Elsa. The swan reappears. Ortrud, seeing its chain, recognises Gottfried, whom she had turned into a swan. She's triumphant because now Lohengrin and the swan, Gottfried, will vanish forever. But Lohengrin releases Gottfried from Ortrud’s spell. She collapses. After Lohengrin has vanished Elsa falls lifeless to the floor.