The aging scholar Faust contemplates the renewal of nature. Hearing peasants sing and dance, he realizes that their simple happiness is something he will never experience. An army marches past in the distance (Hungarian March). Faust doesn't understand why the soldiers are so enthusiastic about glory and fame.
Depressed, Faust has returned to his study. Even the search for wisdom can no longer inspire him. Tired of life, he is about to commit suicide when the sound of church bells and an Easter hymn remind him of his youth, when he still had faith in religion. Suddenly Méphistophélès appears, ironically commenting on Faust's apparent conversion. He offers to take him on a journey, promising him the restoration of his youth, knowledge, and the fulfillment of all his wishes. Faust accepts.
Méphistophélès and Faust arrive at Auerbach's tavern in Leipzig, where Brander, a student, sings a song about a rat whose high life in a kitchen is ended by a dose of poison. The other guests offer an ironic "Amen," and Méphistophélès continues with another song about a flea that brings his relatives to infest a whole royal court (Song of the Flea). Disgusted by the vulgarity of it all, Faust demands to be taken somewhere else.
On a meadow by the Elbe, Méphistophélès shows Faust a dream vision of a beautiful woman named Marguerite, causing Faust to fall in love with her. He calls out her name, and Méphistophélès promises to lead Faust to her. Together with a group of students and soldiers, they enter the town where she lives.
Faust and Méphistophélès hide in Marguerite's room. Faust feels that he will find in her his ideal of a pure and innocent woman ("Merci, doux crepuscule!"). Marguerite enters and sings a ballad about the King of Thule, who always remained sadly faithful to his lost love ("Autrefois, un roi de Thulé"). Méphistophélès summons spirits to enchant and deceive the girl and sings a sarcastic serenade outside her window, predicting her loss of innocence. When the spirits have vanished, Faust steps forward. Marguerite admits that she has dreamed of him, just as he has dreamed of her, and they declare their love for each other. Just then, Méphistophélès bursts in, warning them that the girl's reputation must be saved: the neighbors have learned that there is a man in Marguerite's room and have called her mother to the scene. After a hasty goodbye, Faust and Méphistophélès escape.
Faust has seduced, then abandoned Marguerite, who still awaits his return ("D'amour L'ardente flamme"). She can hear soldiers and students in the distance, which reminds her of the night Faust first came to her house. But this time he is not among them.
Faust calls upon nature to cure him of his world-weariness ("Nature immense, impénétrable et fière"). Méphistophélès appears and tells him that Marguerite is in prison. She has accidentally given her mother too much of a sleeping potion, killing the old woman, and will be hanged the next day. Faust panics, but Méphistophélès claims he can save her-if Faust relinquishes his soul to him. Unable to think of anything but saving Marguerite, Faust agrees. The two ride off on a pair of black horses.
Thinking they are on their way to Marguerite, Faust becomes terrified when he sees demonic apparitions. The landscape becomes more and more horrible and grotesque, and Faust finally realizes that Méphistophélès has taken him directly into hell. Demons and damned spirits greet Méphistophélès in a mysterious infernal language and welcome Faust among them.
Hell has fallen silent after Faust's arrival - the torment he suffers is unspeakable. Marguerite is saved and welcomed into heaven.