Swann's Way is divided into three main sections, plus an 'overture'. The overture describes the unnamed narrator lying in bed, half-asleep, recalling other bedrooms he has known and thinking about when, as a small boy, he would wait desperately for his mother to kiss him good night.
In the first section, Combray, the taste of a madeleine cake dipped in tea makes the narrator involuntarily recall his idyllic childhood in the country village of Combray. The child is an enthusiastic reader, becoming obsessed with the author Bergotte, who is one of the four archetypal 'artist' characters Proust employs in the Search along with Vinteuil (composer), Elstir (painter) and Berma (actress). The boy decides that he wants to become a writer.
The child goes on country walks with his parents. There are two favourite walks: an accessible one known to the family as the Méséglise or Swann's Way as it takes them past the estate of their neighbour, Swann, and the other a longer, more difficult walk called the Guermantes Way which goes past the estate of the aristocratic Guermantes family. The young boy sees these two paths as entirely separate, and they come to represent the familiar, bourgeois world (Swann's Way) and the romantic, yet hard to follow aristocratic world (Guermantes' Way).
In the second section, Swann In Love, the narrator recounts the story of his family's neighbour Charles Swann and his love for Odette de Crecy, a woman notorious for her affairs. Swann, a connoisseur of art and friend of the aristocracy, is initially unmoved when Odette approaches him, but then falls in love with her and begins an affair. As he becomes more infatuated she withdraws from him, and he becomes increasingly, maddeningly jealous, foreshadowing the narrator's jealous relationship with Albertine later in the Search (especially The Captive). Swann and Odette become regulars at the salon of the Verdurins, a bourgeois couple far below the circles in which Swann usually socialises; Proust uses this in a series of comic scenes to satirise the pretentions of bourgeoisie.
After a while, Swann loses interest in Odette and drifts back to his previous life with his friends, including the Duchesse du Guermantes, a figure idolised by the narrator. Here we see that the occupations of the upper classes are just as empty and shallow as those of the Verdurin circle. Swann, reflecting back on his affair, is bitter at the time he 'wasted' loving Odette.
In the third section, Place Names: The Name, we learn that Swann has in fact married Odette, presumably for the sake of their daughter, Gilberte. He is now shunned by society, which is shocked by Odette's scandalous past. The narrator, now a young adolescent in Paris, develops an obsessive crush on Gilberte which comes to nothing. The novel ends with the narrator thinking about Odette's beauty and looking back on her time, wistfully recalling a world that has been lost forever.
The rest of In Search of Lost Time relates the story of the narrator's life, as he grows up, becoming a member of the fashionable society salons in Paris, even coming to know the Guermantes family. He recounts the story of his jealous relationship with Albertine, which echoes Swann's affair with Odette, although it ends in tragedy. At the heart of all six volumes is the narrator's journey towards becoming a writer, and his realisation that the past can only be recaptured through art.