The mood of The Age of Innocence is an overwhelmingly bleak one. The three major characters (Archer, Ellen, and May) are deeply unhappy and tortured for most of the novel. Archer—the protagonist and character to whom the narration stays closest—starts the novel worried about his impending marriage to May because he doesn’t believe they are equals (she is overly “innocent” and he has far more life experience), and his resentment toward her only grows as he falls in love with her cousin Ellen and cannot be with her.
Meanwhile, Ellen starts the novel having escaped from an abusive marriage in Europe only to find herself a social outcast in New York society (as people judge her for her failed marriage). Her fate is only worsened as she falls in love with Archer and then flees after finding out that May has become pregnant with his child. May—who starts the novel “innocent” and unaware of Archer’s cynicism about society—comes to realize that he has been lying to her about his feelings for Ellen and ultimately loses her innocence in order to manipulate Ellen into leaving (by lying about being pregnant before she knew for sure that she was).
All of these characters’ experiences are, in their own ways, quite tragic, and contribute to the tense, unhappy mood of the novel. That said, Wharton does grant readers something of a reprieve at the end of the novel when she flashes forward 26 years into the future. Though May is now dead and Archer still carries a torch for Ellen after more than two decades of marriage, the mood is more hopeful. This comes across in all of the social changes that Archer notices, including how young men can marry women who their families might disapprove of (like his son Dallas marrying Beaufort’s daughter, whose mother was a prostitute). Though Archer ends the story holding onto fantasies about Ellen, Wharton suggests, there is hope for future generations to be with the people they love, whoever they are.