Lolita is a book about a pervert.
The protagonist, Humbert Humbert (yes, his first name is the same as his last name), a creepy European guy, falls madly in love with Dolores Haze, who happens to be twelve at the time. Naturally, he responds to this unsettling development by marrying the girl's mother. The intellectual and poetic Humbert's tragic flaw is that he actually writes shit down about wanting to fuck his wife's twelve year old daughter.
Humbert's wife is clingy and paranoid. She reads his diary then flips out and says she's taking Lolita away and he'll never see her again. He seriously considers killing his wife, but then she runs out into the street and gets hit by a car and dies.
Mr. Tentacles (our beloved Humbert Humbert) is given guardianship of Lolita, and they take a road trip across the country together. Vladimir Nabokov is such a good writer, you find yourself feeling sorry for the crazy pedophile when Lolita runs away.