In a village of vineyards on the banks of the Rhine. Hilarion, a villager hunter and servant of the court as gamekeeper, takes a pause in the hunting party to return early in the morning near Giselle’s house, with whom he is deeply in love. The villagers go to the vineyards to collect the last bunches before the harvest festival. Count Albrecht also arrives at this village with his advisor and friend, enters into a house next to Giselle’ s and comes out dressed as a villager to be able to go unnoticed as a peasant nicknamed Loys and flirt and be alone with the beautiful Giselle. Giselle comes out of her house. Albrecht/Loys swears eternal love to her. She takes a daisy, and petal after petal she tries to know if he loves her or loves her not. At a certain point, she realizes that the response of fate is "no", and then throws the daisy away. Albrecht/Loys picks it up and pretends that it had one more petal. Naive and in love, Giselle believes him. Hilarion interrupts the festivities to make it clear that he and not Loys is who sincerely loves her. They start to fight. Hilarion suspects Loys when he sees him making the gesture of unsheathing the sword as if he were a noble.
The villagers return from the fields, and Giselle invites them to dance with her to celebrate the harvest. Her mother asks her not to do so because she knows that as she is so frail, any effort tires her out. The image of her daughter dying makes her crazy. In her dreams she sees her as one of the Wilis, as a spirit without peace due to unrequited loves. The horn sounds in the distance. Albrecht/Loys recognizes that the sound comes from the hunting party of the Prince of Courtland which is approaching. He leaves in order not to be recognized. Hilarion, alert to his actions, enters the house where Albrecht has disguised as a peasant. The noblemen who participate in the party are greeted with refreshments and the Prince’s daughter, Bathilde, gives Giselle a necklace when she learns that they both are going to get married soon. Once the hunters continue their way, Hilarion appears with Albrecht’s cloak and sword, ready to unmask him as a noble and not a villager. The villagers come back naming Giselle the Harvest Queen. Hilarion exposes Loys as an impostor. Loys denies the accusation. Hilarion takes the horn and calls back the Prince’s retinue. Upon arrival, Bathilde is surprised to see Albrecht disguised as a villager and reveals to Giselle that he is the man to whom she will get married. The fragile Giselle cannot overcome so much evil, deceit and betrayal. She becomes delirious and begins to dance causing her heart to give out.
In a clearing in the woods, near Giselle’s grave, the Wilis dance led by their Queen Myrtha, and fulfill the rite of initiation of Giselle as a member of the sisterhood of all those who died for unrequited love. They are souls who cannot rest, condemned to wander forever. Every night, since the moon rises until dawn, they will seek revenge on any man who dares to go into their domain, forcing them to dance until they die. Hilarion, desperate, has come to mourn at Giselle’s grave in the woods and dies in their hands. Albrecht, repentant, has also come to bring flowers to his beloved’s grave, and is reached by the Wilis, who demand his death. Giselle, despite her pain, decides to protect him and dances with him until dawn to save him from the Wilis. With the first sunbeams, their power over men weakens. Giselle must inexorably go back to her grave and leave Albrecht safe, completely devastated.