'The Age of Innocence' is a novel set in the 1870s, focusing on New York's high society. The main character, Newland Archer, is engaged to a suitable and traditional young woman named May Welland. However, their lives get complicated when Countess Ellen Olenska, May's cousin, returns to New York after leaving her European husband. Newland becomes infatuated with Ellen and struggles between his duty to marry May and his love for Ellen. The novel explores themes of love, societal expectations, and personal freedom.