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 villager 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 takes 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; Loys retrieves it and, by surreptitiously discarding a petal, comes up with the answer “he loves me.” Hilarion interrupts, protesting that he, and not Loys, truly loves Giselle. A quarrel ensues, and Hilarion’s suspicions deepen as Loys instinctively reaches for the sword that, 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 overexerts 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 Loys hastily departs, Hilarion breaks into Loys’ 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 a 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 impostor. When Loys denies the charges and threatens the gamekeeper with his sword, Hilarion blows the hunting horn, a signal for the prince to return. Loys is exposed as an impostor 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.