Giselle begins in the village of Thuringen, located in the German Rhineland. Giselle, a lovely peasant girl with a weak heart and a passion for dancing, is courted by a young man known to her as Loys. He is, in fact, Albrecht, Duke of Silesia, disguised as a peasant. Loys vows eternal love for Giselle, but the mood is shattered by Hilarion, a woodsman. He has long been in love with Giselle, but she rejects him and makes clear her feelings for Loys. Hilarion is suspicious of Loys, and he angrily vows to uncover the true identity of this mystery man and separate the two lovers.
Giselle and Loys are met by friends and villagers on their way from the vineyards, and all join in a dance. But Berthe, Giselle’s mother, admonishes the girl for dancing so much, afraid that her daughter’s heart will give out. She tells Giselle and the villagers the story of the Wilis, young women who died before their wedding day and must spend eternity dancing. This, she fears, will be Giselle’s fate. Berthe leads a reluctant Giselle indoors, and Loys takes his leave.
Horns sound in the distance, signaling the imminent arrival of a hunting party. Hilarion returns and breaks into Loys’ hut as the horns sound again. The hunting party arrives, led by the Duke of Courland and his daughter, Bathilde, who are seeking sustenance.
As Giselle sees to her guests, Bathilde engages her in conversation. The noblewoman inquires whether Giselle has a boyfriend, and Giselle explains that she is engaged. Bathilde responds that she is also engaged and asks after Giselle’s fiancé. Giselle says that she is looking for him but can’t find him. Bathilde is charmed by Giselle, and requests the Duke’s permission to present the girl with her necklace. Giselle is so delighted by the gift that, as a gesture of thanks, she dances for Bathilde.
The Duke and Bathilde go to Giselle’s cottage for a rest, and the hunting party disperses. Hilarion emerges from Loys’ hut holding his rival’s sword. He notices the hunting horn hanging outside Giselle’s cottage, and on closer examination, he sees that it is branded with the same crest as the sword. He feels vindicated, triumphant. But before he can expose Loys’ deception to Giselle, the vintagers return. Hilarion hides the sword and waits.
Giselle’s friends return and crown her Queen of the Vintage. Everyone dances in celebration of the harvest, including Giselle and Loys. But their revelry is interrupted by an angry Hilarion, who rushes toward Giselle and denounces Loys as a deceiver. He presents the sword as proof. Giselle does not want to believe him. Hilarion summons the hunting party with the horn, and Loys, or Albrecht, can no longer conceal his identity. Not only is he a nobleman, but he is engaged to Bathilde! Giselle is distraught beyond measure. She stabs herself with Albrecht’s sword and sinks into madness. Weakened physically and emotionally, she collapses and dies.
Giselle has been buried in a forest, close to a lake. Hilarion comes to grieve at her grave, but does not linger; he senses the presence of Wilis.
Myrtha, Queen of the Wilis, summons her subjects to appear and assist her in initiating Giselle to their sisterhood. The Wilis hide about the forest as Albrecht, full of remorse and sorrow, comes to mourn at Giselle’s grave and seek her forgiveness. She suddenly appears before him, and he runs off in pursuit of her. Meanwhile, Hilarion has been found in the forest by the Wilis. On Myrtha’s orders, they make him dance until he is exhausted and then cast him into the lake, where he dies.
Now Albrecht’s presence is revealed, and Myrtha commands that he, too, must die. Giselle intervenes, telling him to seek shelter at the cross of her grave, where she stands in protection. But the vengeful Myrtha orders Giselle to dance. She obeys, and Albrecht is soon drawn to her. They beg the Wilis to help them, but their pleas are rebuffed. They begin a pas de deux, and Myrtha now realizes how Albrecht will meet his death. She will see to it that he dances until he dies.
A weary Albrecht pleads to put a halt to his dancing. His entreaty is refused. Giselle again pleads for his life, but she cannot sway Myrtha. Albrecht continues to dance, until he collapses from exhaustion. But the darkness of the forest is broken by the first light of dawn, banishing the Wilis. Giselle returns to the earth. Albrecht, overcome by his love for Giselle and by the generosity of her forgiveness, is left to weep at her grave.