The ballet is set in the vineyard country bordering the Rhine. Hilarion, the village huntsman and a gamekeeper to the court, returns from his early morning chores and pauses before a neighboring cottage, the home of Giselle, with whom he is in love. Villagers pass by on their way to the vineyards, where they will harvest the last of the grapes before the Wine Festival.
Count Albrecht arrives with his squire and enters a cottage opposite Giselle’s. He emerges dressed as a peasant, submits his disguise to the squire’s inspection, and dismisses him. Hilarion has witnessed this exchange and is puzzled that the squire should show such deference to this youth, who is known to the villagers as a fellow peasant named Loys. Loys excuses himself from joining the grape-pickers so that he can be alone with Giselle. He swears eternal love, and she makes the traditional test with a daisy–“he loves me, he loves me not…” When it appears the answer will be “not,” she throws the flower away; but Loys retrieves it and, by surreptitiously discarding a petal, comes up with the answer “he loves me.” Hilarion interrupts, protesting that he, not Loys, truly loves Giselle. A quarrel ensues, and Hilarion’s suspicions are deepened as Loys instinctively reaches for the sword which, as a nobleman, he is accustomed to wearing.
The villagers return, and Giselle invites them to join in a dance to celebrate the harvest. Her mother, Berthe, interrupts and warns her that her life may be endangered if she over-exerts herself by dancing. She is struck by a momentary hallucination of her daughter in death. She sees her as a Wili, a restless spirit who has died with her love unrequited.
A horn sounds in the distance, and Loys recognizes it as coming from the hunting party of the Prince of Courland. As he hastily departs, Hilarion breaks into his cottage. Refreshments are served to the hunters, and the Prince’s daughter, Bathilde, gives Giselle a gold necklace when she learns they are both engaged to be married. After the royal party has returned to the hunt, Hilarion emerges from Loys’ cottage with a hunting horn and sword, further evidence that the supposed peasant is, in fact, a nobleman.
The villagers return and proclaim Giselle the Queen of the Wine Festival. Hilarion interrupts to denounce Loys as an imposter. When Loys denies the charges and threatens the gamekeeper with the sword, Hilarion blows the hunting horn, a signal for the Prince to return. Loys is exposed as an imposter when Bathilde reveals that he is her fiancé, Count Albrecht. The shock of learning of Albrecht’s duplicity is too great for Giselle’s frail constitution. Her mind becomes unhinged and she dies of a broken heart–her love unrequited.
The scene is laid in a clearing in the forest near Giselle’s grave. The Wilis are summoned by their Queen, Myrta, to attend the ceremonies which will initiate Giselle into their sisterhood. The Wilis are maidens whose fiancés have failed to marry them before their death. Their love unrequited, they can find no rest, and their spirits are forever destined to roam the earth from midnight to dawn, vengefully trapping any male who enters their domain and forcing him to dance to his death. Hilarion, in search of Giselle, meets his death at their hands. Albrecht arrives to leave flowers on Giselle’s grave. He, too, is trapped and commanded to dance unto death. Giselle resolves to protect him. She dances with him until the clock strikes four, at which hour the Wilis lose their power. Albrecht is rescued from death.