Hilarion, the village gamekeeper, is in love with Giselle. She doesn’t share his feelings, however, being secretly in love with another. Hilarion struggles to get over his one-way love, but is eaten up with a jealousy that dictates his actions and his life.
The peasants return from harvesting, while the village girls have gathered blooms in the forest for the Flower Festival.
Duke Albrecht of Silesia arrives with a bouquet of daisies for Giselle; he has put aside his sword to assume the look of a peasant and not reveal his true identity. He waits for Giselle at their usual meeting place in the forest. Seeing her arrive in the distance, he hides to try and surprise her.
Giselle, delighted with the flowers brought by Albrecht, twice takes a daisy to question Albrecht about his love; each time, the answer is disappointing. Albrecht, in order to please her, delicately plucks a petal and reassures Giselle of his love. Hilarion surprises the two lovers and questions them about Albrecht’s identity, which he does not know. He openly displays his jealousy and confronts the Duke of Silesia. Albrecht, momentarily confused, forgets his peasant appearance and brings a hand to his sheath, in so doing betraying his status as a nobleman.
When the villagers return for the festivities, Giselle introduces Albrecht to them. During the celebrations, she has a weak spell that gives her fiancé a glimpse into the fragile state of her health. Giselle at that moment has a vision of a being all in light, Myrtha, and is disturbed by an apparition that only she seems to have seen.
When Giselle recovers from her weakness, Albrecht sees the Duke of Courland and his court arriving in the distance. He leaves Giselle without explanation. Hilarion, who has remained in the background, discovers Albrecht’s sword and understand who he truly is. He vows to announce the truth to Giselle at the right time.
Bathilde, the true betrothed of Duke Albrecht, arrives with her father, the Duke of Courland. Looking for water, she comes upon Giselle and her mother. Bathilde asks the latter if Giselle is engaged, to which she replies in the affirmative. Dazzled by her beauty, Bathilde offers Giselle a necklace and asks if Hilarion, who has nodded off close by, is her intended. She answers no: her fiancé has taken himself off.
In the midst of the Flower Festival, peasants and friends launch themselves into a joyful dance. Albrecht and Giselle try to be alone somewhere. When they think they are, she finds the courage to kiss him – under the worried eye of her mother and the jealous eye of Hilarion. In his anger, the latter reveals the sword to Giselle, making clear Albrecht’s identity.
Bathilde and the Duke of Courland, back from their walk, overhear the conversation. Seeing the weapon, Giselle questions Bathilde, who confirms that it is indeed the sword of Albrecht, her fiancé. Giselle understands Albrecht’s lie, and is devastated. Madness overcomes her, and the heart in her weak constitution ceases to beat. Giselle dies.
Giselle’s mother has visited her daughter’s grave and returns home after dark.
Myrtha, the queen of the Wilis, appears surrounded by her subjects. They all welcome Giselle as one of their own. The Wilis, ghosts of young women who died after being betrayed by those they loved, haunt the forest once night falls. Seeking revenge, they cast a spell on any man unlucky enough to venture into the woods, making him dance himself to death.
Myrtha and the others disappear when they hear footsteps approaching: it’s Albrecht, in mourning, bringing flowers to Giselle’s grave. Giselle appears to Albrecht, who realizes that she has forgiven him his falsehood.
In the meanwhile, the Wilis have found Hilarion. Intent on his death, they lead him on a mad dance, but end up tiring of him and abandon him in the woods.
When Albrecht discovers the presence of the Wilis, Myrtha gives the order to take him into the forest. Sacrificing herself for the one she loves, Giselle dances until sunup to save Albrecht. The glimmer of dawn soon forces Myrtha and the Wilis to flee. Giselle, through this sacrifice, succeeds in freeing Albrecht. In peace, she disappears forever.