Synopsis

Prologues
In the first prologue, three people, the theatre director, the poet, and an actor (also referred to as the fool), discuss the purpose of the theatre. The director approaches the theatre from a financial perspective, and is looking to make an income by pleasing the crowd; the actor seeks his own glory through fame as an actor; and the poet aspires to create a work of art with meaningful content. Many productions use the same actors later in the play to draw connections between characters: the director reappears as Wagner, the poet as Faust, and the buffoon as Mephistopheles.

The Prologue in the Theatre
The play begins with the prologue in Heaven. In an allusion to the story of Job, Mephistopheles wagers with God for the soul of Faust.
God has decided to "soon lead Faust to clarity", who previously only "served [Him] confusedly". However, to test Faust, he allows Mephistopheles to attempt to lead him astray. God declares that "man still must err, while he doth strive". It is shown that the outcome of the bet is certain, for "a good man, in his darkest impulses, remains aware of the right path", and Mephistopheles is permitted to lead Faust astray only so that he may learn from his misdeeds. That in itself is his main objective...

The Prologue in Heaven: The Wager

Faust's Tragedy
The play proper opens with a monologue by Faust, sitting in his study, contemplating all that he has studied throughout his life. Despite his wide studies, he is dissatisfied with his understanding of the workings of the world, and has determined only that he knows "nothing" after all. Science having failed him, Faust seeks knowledge in Nostradamus, in the "sign of the Macrocosmos", and from an Earth-spirit, still without achieving satisfaction.
As Faust reflects on the lessons of the Earth-spirit, he is interrupted by his famulus, Wagner. Wagner symbolizes the vain scientific type who understands only book-learning, and represents the educated bourgeoisie. His approach to learning is a bright, cold quest, in contrast to Faust, who is led by emotional longing to seek divine knowledge.
Dejected, Faust spies a phial of poison and contemplates suicide. However he is halted by the sound of church bells announcing Easter, which remind him not of Christian duty but of his happier childhood days.

Night
Faust and Wagner take a walk into the town, where people are celebrating Easter. They hail Faust as he passes them because Faust's father, an alchemist himself, cured the plague. Faust is in a black mood. As they walk among the promenading villagers, Faust reveals to Wagner his inner conflict. Faust and Wagner see a poodle, who they do not know is Mephistopheles in disguise, which follows them into the town.

Outside the town gate
Faust returns to his rooms, and the dog follows him. Faust translates the Gospel of John, which presents difficulties, as Faust cannot determine the sense of the first sentence (specifically, the word logos — In the beginning was the Logos, and the Logos was with God, and the Logos was God., currently translated as The Word). Eventually he settles upon "In the beginning was the deed" as the translation.
The words of the Bible agitate the dog, which shows itself as a monster. When Faust attempts to repel it with sorcery, the dog transforms into Mephistopheles, in the disguise of a travelling scholar. After being confronted by Faust as to his identity Mephistopheles proposes to show Faust the pleasures of life. At first Faust refuses, but the devil draws him into a wager, saying that he will show Faust things he has never seen. They sign a pact agreeing that only if Mephistopheles can give Faust a moment in which he no longer wishes to strive, but begs for that moment to go on, can he win Faust's soul:
"If the swift moment I entreat:
Tarry a while! You are so fair!
Then forge the shackles to my feet,
Then I will gladly perish there!
Then let them toll the passing-bell,
Then of your servitude be free,
The clock may stop, its hands fall still,
And time be over then for me!"
"Faust," Norton Critical Edition, lines 1699–1706

Study
In this, and the following scenes, Mephistopheles leads Faust through the "small" and "great" worlds. These scenes confirm what was clear to Faust in his overestimation of his strength: he cannot lose the bet, because he will never be satisfied, and thus will never experience the "great moment" Mephistopheles has promised him. Mephistopheles appears unable to keep the pact, since he prefers not to fulfill Faust's wishes, but rather to separate him from his former existence. He never provides Faust what he wants, instead he attempts to infatuate Faust with superficial indulgences, and thus enmesh him in deep guilt.
In the scene in Auerbach's Cellar, Mephistopheles takes Faust to a tavern, where Faust is bored and disgusted by the drunken revellers. Mephistopheles realizes his first attempt to lead Faust to ruin is aborted, for Faust expects something different.

Auerbach's Cellar in Leipzig

Gretchen's Tragedy
Mephistopheles takes Faust to see a witch, who—with the aid of a magic potion—turns Faust into a handsome young man. Faust sees an image of Helen of Troy in a magic mirror and falls in love. Helen appears spontaneously, without intervention of Mephistopheles, or other magic. She reappears in Faust, Part II. In contrast to the scene in Auerbach's Cellar, where men behaved as animals, here animals (lemurs) behave as men.

Witch's Kitchen
Faust spies Gretchen on the street in her town, and demands Mephistopheles procure her for him. Mephistopheles foresees difficulty, due to Gretchen's uncorrupted nature. He leaves jewelry in her cabinet, arousing her curiosity. Gretchen brings the jewelry to her mother, who is wary of its origin, and donates it to the Church, much to Mephistopheles's infuriation.

On the street
Mephistopheles leaves another chest of jewelry in Gretchen's house. Gretchen innocently shows the jewelry to her neighbour Martha. Martha advises her to secretly wear the jewelry there, in her house.
Mephistopheles brings Martha the news that her long absent husband has died. He arranges with Martha to bring another witness to meet her in the garden, requesting her also to bring Gretchen to the meeting.
In the previous scene, Faust was not prepared to lie to meet Gretchen. Now he is so controlled by his desire for Gretchen that he consents to lie in order to see her.

The neighbour's house
At the garden meeting, Martha ironically flirts with Mephistopheles, and he is at pains to reject her unconcealed advances. Gretchen confesses her love to Faust, but she knows instinctively that his companion (Mephistopheles) has improper motives.
Gretchen presents Faust with the famous question "Now tell me, how do you take religion?" She wants to admit Faust to her room, but fears her mother. Faust gives Gretchen's mother a bottle containing a sleeping potion. Catastrophically, the potion is poisonous, and the tragedy takes its course.

Garden
In the following scenes Gretchen has the first premonitions that she is pregnant. Gretchen and Martha's discussion of an unmarried mother, in the scene at the Well, confirms the reader's suspicion of Gretchen's pregnancy. Gretchen is distressed to discover the poor place in society of such women.
Valentine, Gretchen's brother, is enraged by her liaison with Faust and challenges him to a duel. Guided by Mephistopheles Faust defeats Valentine, who curses Gretchen just before he dies.

At the well
Gretchen seeks comfort in the church, but she is tormented by an Evil Spirit who whispers in her ear, reminding her of her guilt.
This scene is generally considered to be the finest in the play, the Evil Spirit's tormenting accusations and Gretchen's attempts to resist them are interwoven with verses of the Latin hymn Dies Irae (Day of Wrath), which is being sung in the background.

Walpurgisnacht
Mephistopheles procures the key to the dungeon, and puts the guards to sleep, so that Faust may enter. Gretchen is no longer subject to the illusion of youth upon Faust, and initially does not recognize him. Faust attempts to persuade her to escape, but she refuses because she recognizes that Faust no longer loves her, but pities her. When she sees Mephistopheles, she is frightened and implores to heaven: "Judgment of God! To thee my soul I give!". Mephistopheles pushes Faust from the prison with the words: "She now is judged" (Sie ist gerichtet). Gretchen's salvation, however, is proven by voices from above: "is saved" (ist gerettet).