John Ray, Jr., Ph.D. writes in a foreword that Humbert Humbert, author of the following manuscript, titled "Lolita, or the Confession of a White Widowed Male," died in jail just before his trial was to start in 1952.
Humbert narrates hereafter. He details his European childhood and background as a scholar and relates his tragic childhood love for Annabel Leigh, whose death traumatized Humbert. Humbert is now obsessively attracted to "nymphets," young girls who possess a mysterious seductive power.
After shuttling around some mental institutions and doing odd writing jobs, Humbert lands in the New England town of Ramsdale. He takes a room at the house of widower Charlotte Haze because her beautiful young daughter, Lolita, reminds him of Annabel. Humbert lusts after and flirts with Lolita, but is afraid to do anything lest the repulsive Haze, who wants Humbert, discover her lodger's pedophilia. Lolita goes off to summer camp, and Humbert reluctantly marries Haze, since it is his only chance to keep Lolita in his life.
Humbert toys with the idea of killing Haze, but is unable to do it. She discovers his diary, filled with entries about his love for Lolita and hatred for her, and tells him she is leaving. However, she is immediately hit by a car, and Humbert picks Lolita up at camp. He eventually breaks the news about her mother's death, and at a hotel called The Enchanted Hunter, they have sex for the first time. A strange man seems to take a keen interest in them.
Humbert and Lolita drive across the U.S. for one year. Humbert threatens to put Lolita in an orphanage if she does not comply with his sexual demands. Humbert gets a job at Beardsley College and enrolls Lolita in the girls' school there. Lolita's desire to socialize with boys strains her relationship with Humbert, and he finally agrees to let her participate in a school play called "The Enchanted Hunters."
Humbert suspects Lolita of infidelity, and they leave for another road trip. A man who resembles a relative of Humbert's named Trapp seems to be following them, and Lolita appears to be in contact with him. When Lolita gets sick and is placed in a doctor's office, she is taken away by the man who resembles Trapp. Humbert tries to find her for the next two years, but to no avail. He takes up with a woman named Rita for two years until he receives a letter from Lolita, now married, pregnant, and asking for money.
Humbert plans to kill Lolita's husband, but when he visits them, finds out that her kidnaper was actually Clare Quilty, a playwright with whom Lolita was in love. When she refused to participate in his child pornography films, he rejected her. Lolita declines Humbert's invitation to live with him, and he leaves heartbroken.
Humbert finds out where Quilty lives and, after talking with Quilty and shooting him numerous times, kills him. Humbert is arrested and put in jail, where he finishes his memoir. As we learned from the foreword, he died soon after in captivity, and Lolita died while giving childbirth that Christmas.